This document summarizes an investigation of Newtonian fluid flow through a two-dimensional sudden expansion and sudden contraction flow passage. The study uses computational fluid dynamics to simulate fluid flow through axisymmetric sudden contraction and sudden expansion geometries. It compares flow characteristics like recirculation zone size, reattachment length, and recirculating flow strength between sudden contraction and sudden expansion flows. The effects of varying parameters like Reynolds number, expansion/contraction ratio, and flow direction are explored to understand flow behavior in these geometries.
unsteady flow simulation along staggered cylinder arrangementRamakant Pandey
This document summarizes an unsteady flow simulation around a square cylinder using an upstream rod. It includes an introduction on drag forces on bluff bodies, an overview of how streamlined shapes produce less drag than bluff bodies, and the importance of drag reduction. It then reviews relevant literature on similar studies, identifies gaps in the literature, and outlines the objectives of this study. The study will simulate flow using a square cylinder with an upstream rod, varying parameters like staggered angle, rod diameter and spacing. It will aim to find optimized conditions that produce the least drag. The computational setup and governing equations used in the simulation are also summarized.
Large eddy simulation of the flow over a circular cylinder at high reynolds n...Jesús Martínez
The issue of numerical study of turbulent flow over a circular cylinder for different Reynolds numbers has been studied over almost 20 years. During those two decades, there have been successes and failures in the numerical models. This paper presents the implementation of the method of large eddy simulation (LES) to solve the problem of the external flow over a cylinder under a subcritical Reynolds number (Re = 1.4E +5). The purpose is to evaluate the performance of a computational method and complement experimental and numerical data presented in the literature, this as part of a research work which attempts to explain a method of passive drag reduction.
Modification of the casagrandes equation of phreatic lineIAEME Publication
The document presents an experimental study to modify Casagrande's equation for determining the phreatic line in an earthen dam. A physical model of an earth-fill dam was constructed using sandy silt soil. Phreatic lines were traced for the model with and without a horizontal filter. The experimental results were compared to Casagrande's analytical solution. Regression modeling was then used to derive a new, more accurate equation to determine the phreatic line position based on the experimental data for dams with sandy silt soils. The modified equation was found to estimate the phreatic line location more precisely than Casagrande's original equation.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses flow characteristics over broad crested weirs and stepped weirs. It begins with definitions of broad crested weirs and their advantages. Previous studies on broad crested weirs are summarized that examined factors like rounded edges, discharge coefficients, and separation zones. The document then describes a physical model experiment conducted in a laboratory flume to study a broad crested weir and stepped weir. Numerical modeling using FLUENT software is also discussed to simulate flow over the weirs using the volume of fluid method. The objectives are to examine laboratory data and 2D numerical modeling results to compare free surface profiles.
This document describes a numerical study of flow and energy dissipation in stepped spillways using the FLUENT software. Two stepped spillway models with 5 and 10 steps were analyzed for different flow rates. The k-ε turbulence model and volume of fluid method were used to model turbulence and free surface flow. Numerical results for flow patterns, velocities, and energy dissipation were compared to experimental data from other studies, showing good agreement with errors less than 2%. The results indicate that increasing the flow rate or number of steps reduces energy dissipation, while decreasing step height or length also reduces dissipation.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
In this paper, the unsteady motion of a spherical particle rolling down an inclined tube in a
Newtonian fluid for a range of Reynolds numbers was solved using a simulation method called
the Differential Transformation Method (DTM). The concept of differential transformation is
briefly introduced, and then we employed it to derive solution of nonlinear equation. The
obtained results for displacement, velocity and acceleration of the motion from DTM are
compared with those from numerical solution to verify the accuracy of the proposed method.
The effects of particle diameter (size), continues phase viscosity and inclination angles was
studied. As an important result it was found that the inclination angle does not affect the
acceleration duration. The results reveal that the Differential Transformation Method can achieve suitable results in predicting the solution of such problems.
unsteady flow simulation along staggered cylinder arrangementRamakant Pandey
This document summarizes an unsteady flow simulation around a square cylinder using an upstream rod. It includes an introduction on drag forces on bluff bodies, an overview of how streamlined shapes produce less drag than bluff bodies, and the importance of drag reduction. It then reviews relevant literature on similar studies, identifies gaps in the literature, and outlines the objectives of this study. The study will simulate flow using a square cylinder with an upstream rod, varying parameters like staggered angle, rod diameter and spacing. It will aim to find optimized conditions that produce the least drag. The computational setup and governing equations used in the simulation are also summarized.
Large eddy simulation of the flow over a circular cylinder at high reynolds n...Jesús Martínez
The issue of numerical study of turbulent flow over a circular cylinder for different Reynolds numbers has been studied over almost 20 years. During those two decades, there have been successes and failures in the numerical models. This paper presents the implementation of the method of large eddy simulation (LES) to solve the problem of the external flow over a cylinder under a subcritical Reynolds number (Re = 1.4E +5). The purpose is to evaluate the performance of a computational method and complement experimental and numerical data presented in the literature, this as part of a research work which attempts to explain a method of passive drag reduction.
Modification of the casagrandes equation of phreatic lineIAEME Publication
The document presents an experimental study to modify Casagrande's equation for determining the phreatic line in an earthen dam. A physical model of an earth-fill dam was constructed using sandy silt soil. Phreatic lines were traced for the model with and without a horizontal filter. The experimental results were compared to Casagrande's analytical solution. Regression modeling was then used to derive a new, more accurate equation to determine the phreatic line position based on the experimental data for dams with sandy silt soils. The modified equation was found to estimate the phreatic line location more precisely than Casagrande's original equation.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
The document discusses flow characteristics over broad crested weirs and stepped weirs. It begins with definitions of broad crested weirs and their advantages. Previous studies on broad crested weirs are summarized that examined factors like rounded edges, discharge coefficients, and separation zones. The document then describes a physical model experiment conducted in a laboratory flume to study a broad crested weir and stepped weir. Numerical modeling using FLUENT software is also discussed to simulate flow over the weirs using the volume of fluid method. The objectives are to examine laboratory data and 2D numerical modeling results to compare free surface profiles.
This document describes a numerical study of flow and energy dissipation in stepped spillways using the FLUENT software. Two stepped spillway models with 5 and 10 steps were analyzed for different flow rates. The k-ε turbulence model and volume of fluid method were used to model turbulence and free surface flow. Numerical results for flow patterns, velocities, and energy dissipation were compared to experimental data from other studies, showing good agreement with errors less than 2%. The results indicate that increasing the flow rate or number of steps reduces energy dissipation, while decreasing step height or length also reduces dissipation.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
In this paper, the unsteady motion of a spherical particle rolling down an inclined tube in a
Newtonian fluid for a range of Reynolds numbers was solved using a simulation method called
the Differential Transformation Method (DTM). The concept of differential transformation is
briefly introduced, and then we employed it to derive solution of nonlinear equation. The
obtained results for displacement, velocity and acceleration of the motion from DTM are
compared with those from numerical solution to verify the accuracy of the proposed method.
The effects of particle diameter (size), continues phase viscosity and inclination angles was
studied. As an important result it was found that the inclination angle does not affect the
acceleration duration. The results reveal that the Differential Transformation Method can achieve suitable results in predicting the solution of such problems.
This document outlines the syllabus for a Strength of Materials course taught at Visvesvaraya Technological University. The course is a 3rd semester undergraduate class in Civil Engineering. It covers 5 modules: simple stresses and strains, compound stresses, shear force and bending moment in beams, torsion in circular shafts, and bending and shear stresses in beams. The course aims to teach students how to evaluate the strength of structural elements and materials. It will cover internal forces, failure concepts, torsion analysis, and beam design. Assessment includes class participation, exams, and a focus on applying concepts to solve engineering problems.
Thermohydraulic Performance of a Series of In-Line Noncircular Ducts in a Par...Carnegie Mellon University
Heat transfer and fluid flow characteristics for two-dimensional laminar flow at low Reynolds number for five in-line ducts of
various nonconventional cross-sections in a parallel plate channel are studied in this paper.The governing equations were solved
using finite-volumemethod.CommercialCFDsoftware,ANSYS Fluent 14.5,was used to solve this problem.Atotal of three different
nonconventional, noncircular cross-section ducts and their characteristics are compared with those of circular cross-section ducts.
Shape-2 ducts offered minimum flow resistance and maximum heat transfer rate most of the time. Shape-3 ducts at Re < 100 and Shape-2 ducts at Re > 100 can be considered to give out the optimum results.
Effect of Geometry on Variation of Heat Flux and Drag for Launch Vehicle -- Z...Abhishek Jain
Above Research Paper can be downloaded from www.zeusnumerix.com
The research paper aims at studying the variation of the geometry of the launch vehicle nose and its effect on heat flux. CFDExpert software is first validated on NASA's hyperballistic model and then used on proposed geometries. Various nose radius and blending shapes are studied for effect on drag and heat flux. Cone ogive shape is found to decrease heat flux with an insignificant increase in drag. Authors Abhishek Jain (Zeus Numerix), Rohan Kedar and Prof V Kalamkar (SPCOE).
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
This document summarizes a study that used computational fluid dynamics (CFD) to simulate flow patterns around six types of triangular porous weirs with various upstream and downstream slopes. The study examined flow depth, discharge through the porous media, and velocity fields. Key findings include:
- Weirs with steeper upstream slopes produced lower upstream water levels and higher ratios of flow passing through the weir.
- The weir with a 30° downstream slope produced the highest upstream head and lowest discharge coefficient.
- Flow through the porous weirs reduced upstream water levels and vortex areas compared to solid weirs.
Effect of inclined hump on the turbulence intensities and flow characteristic...eSAT Journals
Abstract In this paper, an experimental study was carried out to investigate the turbulence field and flow characteristics in the separated flow through inclined hump in water structures in rectangular channel using Laser. To study the variation of the turbulence, energy loss, relative energy (efficiency) and relative depth with main parameters affecting the inclined hump These parameters include the hump angle, relative height, upstream Froude number, bottom slope. Non-dimensional design curves are provided to relate the turbulence intensities and flow characteristics. The results show that, the variation of the energy loss increases till of hump angle about 45°. This rate of increase decreases about this value of angle of hump. The energy loss increases with the increasing of bed slope and relative height. The energy loss is quite high at a relative contraction of 0.3. Also, the results clearly showed the dependence of the hump inclination angle on the turbulence intensities. For hump angle ≥ 20°, the turbulence intensity in the separation zones was growing with increasing hump angles and the maximum was observed for hump inclination angles between 20° and 30°. The results indicated that, the most significant differences in flow structures occurred with hump angle less than 45°. Keywords: Energy loss-Turbulence intensities-Water structures- Hump-Laser Technique-Hump angle-Bottom slope-Relative height-Relative depth- Froude number-separation zones.
IRJET- Numerical Analysis of Slurry Flow Characteristics Through Horizontal P...IRJET Journal
This document summarizes a numerical study of slurry flow characteristics in a horizontal pipeline using computational fluid dynamics (CFD). The study models the flow of particles 0.125 mm in size and 2.47 specific gravity through a 4m long, 54.9 mm diameter pipe. Simulations were conducted at velocities of 2 m/s and 5 m/s and particle concentrations of 30% and 40% to analyze solid concentration distribution, velocity distribution, and pressure drop. An Eulerian two-phase model with RNG k-epsilon turbulence modeling was used to simulate the solid-liquid flow and solve the governing equations throughout the computational domain.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Aerodynamic Analysis of Low Speed Turbulent Flow Over A Delta WingIJRES Journal
Delta wing has been a subject of intense research since decades due to decades due to inherent characteristics of generating increased nonlinear lift due to vortex dominated flows. Lot of work has been carried out in order to understand the vortex dominated flows on the delta wing. The delta wing is a wing platform in the form of a triangle. Aerodynamics of wings with moderate sweep angle is recognized by the aerospace community as a challenging problem. In spite of its potential application in military aircraft, the understanding of the aerodynamics of such wings is far from complete. In order to address this situation, the present work is initiated to compute the 3D turbulent flow field over sharp edged finite wings with a diamond shaped plan forms and moderate sweep angle. The detailed flow pattern and surface pressure distribution may further indicate the appropriate kind of flow control during flight operation of such wings. The flow field is computed using an in-house developed CFD code RANS3D.
1. The document presents a pressure transient analysis method for a reservoir with an internal circular boundary, such as a gas cap.
2. The problem is modeled using the Laplace transform solution of the diffusivity equation with boundary conditions. This allows developing a generalized type curve solution.
3. A new generalized type curve is presented, which allows estimating the permeability of the reservoir section within the boundary and the transient time to reach the boundary through type curve matching, without using the double straight line technique.
This document provides an overview of flow nets and seepage analysis. It begins by defining the objectives of understanding basic principles of two-dimensional flows through soil media. It then discusses confined and unconfined flow problems and the objectives of analyzing them. The document introduces key concepts like Laplace's equation, Darcy's law, flow nets, and explains how to estimate seepage quantity using flow nets. It also discusses exit gradients, piping effects, and filter design to prevent failures from piping. The overall summary is that the document presents principles and methods for analyzing seepage problems in geotechnical engineering using flow nets and discusses their applications.
This document provides an overview of reservoir engineering fundamentals including:
- Three types of reservoir fluids based on compressibility: incompressible, slightly compressible, and compressible.
- Three flow regimes in reservoirs: steady-state, unsteady-state, and pseudosteady-state.
- Common reservoir geometries that influence fluid flow including radial, linear, spherical, and hemispherical.
- Darcy's law and its applications to steady-state fluid flow in reservoirs, including for different fluid types and geometries.
Numerical Simulation of Flow between Two Parallel Co-Rotating DiscsDr. Amarjeet Singh
The study of fluid flow between two rotating discs
aims to predict flow characteristics. In this paper numerical
simulation is used to investigate axisymmetric swirling flow
between two parallel co-rotating discs.
Methodology entails, firstly, inputing parameters
from CFD software are into previos study developed
dimensionless radial velocity model for flow between two
discs to obtain dimensional radial velocity of the model.
Secondly, previous study parameters are used to perform
numerical simulation on laminar and turbulent flows
between two parallel co-rotating discs. The numerical
simulation results are compared to previous study results.
Then comparative numerical simulations was carried out on
laminar and turbulent flows using CFD software.
Results obtained showed that for the this study
dimensional radial velocity and previous study
dimensionless radial velocity, radial velocity distribution
increase proportionately from the disc surface at 0m/s to
2208.00m/s and 0 to 0.0002396 respectively, at the domain
centre. And both results satisfy initial inlet and boundary
conditions with resultant parabolic profiles. In the study, it
is shown that turbulent flow radial velocity profile is
smoother than for laminar flow. The radial velocity
increases from 0 at the walls to 0.15m/s before decreasing to
- 0.2m/s at the mid-centre for laminar flow while for
turbulent flow the radial velocity intitially increases from 0
at the walls to 0.15m/s before decreasing to -0.06m/s at the
discs centre; while for laminar flow, swirl velocity decrease
from approximately 2.55m/s to 0.55m/s and for turbulent
flow the swirl velocity decrease from approximately 2.84m/s
to 1.62m/s. The turbulent flow swirl velocity profile seen to
be smoother than for laminar flow around the discs centre.
The study further showed that for fluid near the discs
surfaces radial velocity net momentum is radially towards
the outlet with flow laminar in the boundary layer region
and the velocity turbulent towards the domain centre. For
static pressure, laminar flow maximum and minimum static
pressure 2.48pa and -0.033pa respectively, while for
turbulent flow maximum and minimum static pressure were
0.00 and -0.0024pa.
The developed previous study model can therefore
be used to predict radial velocity distribution between
steady axisymmetric flow between two parallel co-rotating
discs.
This document provides an overview of reservoir engineering concepts related to analyzing fluid flow in reservoirs, including:
1. It introduces dimensionless variables like dimensionless pressure (pD) that are used to simplify solutions to the diffusivity equation governing fluid flow. pD solutions are presented for both infinite-acting and finite radial reservoirs.
2. Methods for solving the diffusivity equation for compressible (gas) fluids are described, including exact (m(p)-solution) and approximate (pressure-squared, pressure) methods.
3. The dimensionless forms of these solutions - like dimensionless real gas pseudopressure drop (ψD) - are also introduced and their calculation methods explained.
Peristaltic flow of blood through coaxial vertical channel with effect of mag...ijmech
The present paper investigates the effects of peristaltic flow of blood through coaxial vertical channel with
effect of magnetic field: blood flow study.The effects of various physical parameters on axial velocity and
pressure gradient have been computed numerically. It is observed that the maximum velocity increases
with increase in Magnetic field (M) even though for phase shiptııııı/ 4 for all the two cases
= - 0.5,
= -1. However, opposite effects are noticed for
= 0.5,
= 1.
Experimental flow visualization for flow around multiple side-by-side circula...Santosh Sivaramakrishnan
The document summarizes an experimental study of flow visualization around four side-by-side circular cylinders at a Reynolds number of 190 and spacing-to-diameter ratios from 1.0 to 6.0. The study found that at low spacing, the flow regime was chaotic, while at high spacing above 4.0, the vortex shedding was synchronous. Between spacing ratios of 1.0 to 3.0, the flow transitioned through a quasi-periodic regime as the shed vortices interacted at increasing distances from the cylinders with increasing spacing. The results provide benchmark data for numerical simulations of flow around multiple circular cylinders.
Measuring Hydrualic Conductivity Using Petro Physical Measurements 2013 compa...Christopher Estevez
This summary provides the key points from the document in 3 sentences:
The document discusses various methods for measuring hydraulic conductivity in soils more accurately in the field, including using gravitational methods for saturated soils and the Proportional Cylinder and Arya-Dierolf models for unsaturated soils. It analyzes modifying Darcy's law to account for centrifugal force when measuring saturated soils and how the Proportional Cylinder and Arya-Dierolf models can help determine unsaturated pore size and estimate hydraulic conductivity. Accurately measuring hydraulic conductivity is important for environmental cleanup efforts to more efficiently remove contaminants from lands.
Numerical Investigation of Head Frontal Velocity of Non-conservative Dense Fl...IRJET Journal
This document presents a numerical investigation of the head frontal velocity of non-conservative dense flows in small inclined beds. The study uses the Fluent numerical code to simulate dense flow frontal velocity two-dimensionally using the Euler-Lagrange method. The results from the numerical model show good agreement with experimental results and help analyze fluid movement patterns at different scales. Key findings include that head frontal velocity remains fixed in the numerical and experimental models from 3-11 meters from the inlet, and the Fluent code is suitable for simulating these types of flows when compared to empirical experimental results.
The Philadelphia Inquirer, Philadelphia Daily News, and philly.com hired a PR firm to help a new group of investors relaunch the brands after acquiring them. The PR firm executed an aggressive media relations campaign highlighting the marketing expertise of the new team. This helped gain coverage for the relaunch in local, trade, and national media. As a result, readership grew and web traffic increased significantly. The PR firm also helped launch successful events that brought new readers and revenue.
This document discusses four students - Phoebe, Megan, Tyler, and Alexis - who committed suicide after experiencing cyberbullying. It provides brief biographical information about each student, noting what careers they may have pursued based on their interests. The document also includes links to news coverage about each case, asking the reader to consider what could have been done differently to change the outcomes and assigning a reaction paper on this topic using MLA formatting.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document discusses developing accessibility levels in rural areas of India. It focuses on a study area between Rajam and Srikakulam in Andhra Pradesh, India. Household and onboard surveys were conducted to collect data on trip characteristics, purposes, lengths, and satisfaction levels. Accessibility levels were calculated for activities like work, college etc. based on their weights or importance. Some villages like Palakandyam, Santa Uriti and Reddipeta had poor accessibility levels. Measures to increase accessibility include improving transport facilities to key activities. A travel demand model was developed to forecast future trips up to 2018 based on population growth rates. Costs were estimated for different modes of transport to identify more cost effective options.
This document outlines the syllabus for a Strength of Materials course taught at Visvesvaraya Technological University. The course is a 3rd semester undergraduate class in Civil Engineering. It covers 5 modules: simple stresses and strains, compound stresses, shear force and bending moment in beams, torsion in circular shafts, and bending and shear stresses in beams. The course aims to teach students how to evaluate the strength of structural elements and materials. It will cover internal forces, failure concepts, torsion analysis, and beam design. Assessment includes class participation, exams, and a focus on applying concepts to solve engineering problems.
Thermohydraulic Performance of a Series of In-Line Noncircular Ducts in a Par...Carnegie Mellon University
Heat transfer and fluid flow characteristics for two-dimensional laminar flow at low Reynolds number for five in-line ducts of
various nonconventional cross-sections in a parallel plate channel are studied in this paper.The governing equations were solved
using finite-volumemethod.CommercialCFDsoftware,ANSYS Fluent 14.5,was used to solve this problem.Atotal of three different
nonconventional, noncircular cross-section ducts and their characteristics are compared with those of circular cross-section ducts.
Shape-2 ducts offered minimum flow resistance and maximum heat transfer rate most of the time. Shape-3 ducts at Re < 100 and Shape-2 ducts at Re > 100 can be considered to give out the optimum results.
Effect of Geometry on Variation of Heat Flux and Drag for Launch Vehicle -- Z...Abhishek Jain
Above Research Paper can be downloaded from www.zeusnumerix.com
The research paper aims at studying the variation of the geometry of the launch vehicle nose and its effect on heat flux. CFDExpert software is first validated on NASA's hyperballistic model and then used on proposed geometries. Various nose radius and blending shapes are studied for effect on drag and heat flux. Cone ogive shape is found to decrease heat flux with an insignificant increase in drag. Authors Abhishek Jain (Zeus Numerix), Rohan Kedar and Prof V Kalamkar (SPCOE).
International Journal of Computational Engineering Research(IJCER)ijceronline
International Journal of Computational Engineering Research(IJCER) is an intentional online Journal in English monthly publishing journal. This Journal publish original research work that contributes significantly to further the scientific knowledge in engineering and Technology
This document summarizes a study that used computational fluid dynamics (CFD) to simulate flow patterns around six types of triangular porous weirs with various upstream and downstream slopes. The study examined flow depth, discharge through the porous media, and velocity fields. Key findings include:
- Weirs with steeper upstream slopes produced lower upstream water levels and higher ratios of flow passing through the weir.
- The weir with a 30° downstream slope produced the highest upstream head and lowest discharge coefficient.
- Flow through the porous weirs reduced upstream water levels and vortex areas compared to solid weirs.
Effect of inclined hump on the turbulence intensities and flow characteristic...eSAT Journals
Abstract In this paper, an experimental study was carried out to investigate the turbulence field and flow characteristics in the separated flow through inclined hump in water structures in rectangular channel using Laser. To study the variation of the turbulence, energy loss, relative energy (efficiency) and relative depth with main parameters affecting the inclined hump These parameters include the hump angle, relative height, upstream Froude number, bottom slope. Non-dimensional design curves are provided to relate the turbulence intensities and flow characteristics. The results show that, the variation of the energy loss increases till of hump angle about 45°. This rate of increase decreases about this value of angle of hump. The energy loss increases with the increasing of bed slope and relative height. The energy loss is quite high at a relative contraction of 0.3. Also, the results clearly showed the dependence of the hump inclination angle on the turbulence intensities. For hump angle ≥ 20°, the turbulence intensity in the separation zones was growing with increasing hump angles and the maximum was observed for hump inclination angles between 20° and 30°. The results indicated that, the most significant differences in flow structures occurred with hump angle less than 45°. Keywords: Energy loss-Turbulence intensities-Water structures- Hump-Laser Technique-Hump angle-Bottom slope-Relative height-Relative depth- Froude number-separation zones.
IRJET- Numerical Analysis of Slurry Flow Characteristics Through Horizontal P...IRJET Journal
This document summarizes a numerical study of slurry flow characteristics in a horizontal pipeline using computational fluid dynamics (CFD). The study models the flow of particles 0.125 mm in size and 2.47 specific gravity through a 4m long, 54.9 mm diameter pipe. Simulations were conducted at velocities of 2 m/s and 5 m/s and particle concentrations of 30% and 40% to analyze solid concentration distribution, velocity distribution, and pressure drop. An Eulerian two-phase model with RNG k-epsilon turbulence modeling was used to simulate the solid-liquid flow and solve the governing equations throughout the computational domain.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Aerodynamic Analysis of Low Speed Turbulent Flow Over A Delta WingIJRES Journal
Delta wing has been a subject of intense research since decades due to decades due to inherent characteristics of generating increased nonlinear lift due to vortex dominated flows. Lot of work has been carried out in order to understand the vortex dominated flows on the delta wing. The delta wing is a wing platform in the form of a triangle. Aerodynamics of wings with moderate sweep angle is recognized by the aerospace community as a challenging problem. In spite of its potential application in military aircraft, the understanding of the aerodynamics of such wings is far from complete. In order to address this situation, the present work is initiated to compute the 3D turbulent flow field over sharp edged finite wings with a diamond shaped plan forms and moderate sweep angle. The detailed flow pattern and surface pressure distribution may further indicate the appropriate kind of flow control during flight operation of such wings. The flow field is computed using an in-house developed CFD code RANS3D.
1. The document presents a pressure transient analysis method for a reservoir with an internal circular boundary, such as a gas cap.
2. The problem is modeled using the Laplace transform solution of the diffusivity equation with boundary conditions. This allows developing a generalized type curve solution.
3. A new generalized type curve is presented, which allows estimating the permeability of the reservoir section within the boundary and the transient time to reach the boundary through type curve matching, without using the double straight line technique.
This document provides an overview of flow nets and seepage analysis. It begins by defining the objectives of understanding basic principles of two-dimensional flows through soil media. It then discusses confined and unconfined flow problems and the objectives of analyzing them. The document introduces key concepts like Laplace's equation, Darcy's law, flow nets, and explains how to estimate seepage quantity using flow nets. It also discusses exit gradients, piping effects, and filter design to prevent failures from piping. The overall summary is that the document presents principles and methods for analyzing seepage problems in geotechnical engineering using flow nets and discusses their applications.
This document provides an overview of reservoir engineering fundamentals including:
- Three types of reservoir fluids based on compressibility: incompressible, slightly compressible, and compressible.
- Three flow regimes in reservoirs: steady-state, unsteady-state, and pseudosteady-state.
- Common reservoir geometries that influence fluid flow including radial, linear, spherical, and hemispherical.
- Darcy's law and its applications to steady-state fluid flow in reservoirs, including for different fluid types and geometries.
Numerical Simulation of Flow between Two Parallel Co-Rotating DiscsDr. Amarjeet Singh
The study of fluid flow between two rotating discs
aims to predict flow characteristics. In this paper numerical
simulation is used to investigate axisymmetric swirling flow
between two parallel co-rotating discs.
Methodology entails, firstly, inputing parameters
from CFD software are into previos study developed
dimensionless radial velocity model for flow between two
discs to obtain dimensional radial velocity of the model.
Secondly, previous study parameters are used to perform
numerical simulation on laminar and turbulent flows
between two parallel co-rotating discs. The numerical
simulation results are compared to previous study results.
Then comparative numerical simulations was carried out on
laminar and turbulent flows using CFD software.
Results obtained showed that for the this study
dimensional radial velocity and previous study
dimensionless radial velocity, radial velocity distribution
increase proportionately from the disc surface at 0m/s to
2208.00m/s and 0 to 0.0002396 respectively, at the domain
centre. And both results satisfy initial inlet and boundary
conditions with resultant parabolic profiles. In the study, it
is shown that turbulent flow radial velocity profile is
smoother than for laminar flow. The radial velocity
increases from 0 at the walls to 0.15m/s before decreasing to
- 0.2m/s at the mid-centre for laminar flow while for
turbulent flow the radial velocity intitially increases from 0
at the walls to 0.15m/s before decreasing to -0.06m/s at the
discs centre; while for laminar flow, swirl velocity decrease
from approximately 2.55m/s to 0.55m/s and for turbulent
flow the swirl velocity decrease from approximately 2.84m/s
to 1.62m/s. The turbulent flow swirl velocity profile seen to
be smoother than for laminar flow around the discs centre.
The study further showed that for fluid near the discs
surfaces radial velocity net momentum is radially towards
the outlet with flow laminar in the boundary layer region
and the velocity turbulent towards the domain centre. For
static pressure, laminar flow maximum and minimum static
pressure 2.48pa and -0.033pa respectively, while for
turbulent flow maximum and minimum static pressure were
0.00 and -0.0024pa.
The developed previous study model can therefore
be used to predict radial velocity distribution between
steady axisymmetric flow between two parallel co-rotating
discs.
This document provides an overview of reservoir engineering concepts related to analyzing fluid flow in reservoirs, including:
1. It introduces dimensionless variables like dimensionless pressure (pD) that are used to simplify solutions to the diffusivity equation governing fluid flow. pD solutions are presented for both infinite-acting and finite radial reservoirs.
2. Methods for solving the diffusivity equation for compressible (gas) fluids are described, including exact (m(p)-solution) and approximate (pressure-squared, pressure) methods.
3. The dimensionless forms of these solutions - like dimensionless real gas pseudopressure drop (ψD) - are also introduced and their calculation methods explained.
Peristaltic flow of blood through coaxial vertical channel with effect of mag...ijmech
The present paper investigates the effects of peristaltic flow of blood through coaxial vertical channel with
effect of magnetic field: blood flow study.The effects of various physical parameters on axial velocity and
pressure gradient have been computed numerically. It is observed that the maximum velocity increases
with increase in Magnetic field (M) even though for phase shiptııııı/ 4 for all the two cases
= - 0.5,
= -1. However, opposite effects are noticed for
= 0.5,
= 1.
Experimental flow visualization for flow around multiple side-by-side circula...Santosh Sivaramakrishnan
The document summarizes an experimental study of flow visualization around four side-by-side circular cylinders at a Reynolds number of 190 and spacing-to-diameter ratios from 1.0 to 6.0. The study found that at low spacing, the flow regime was chaotic, while at high spacing above 4.0, the vortex shedding was synchronous. Between spacing ratios of 1.0 to 3.0, the flow transitioned through a quasi-periodic regime as the shed vortices interacted at increasing distances from the cylinders with increasing spacing. The results provide benchmark data for numerical simulations of flow around multiple circular cylinders.
Measuring Hydrualic Conductivity Using Petro Physical Measurements 2013 compa...Christopher Estevez
This summary provides the key points from the document in 3 sentences:
The document discusses various methods for measuring hydraulic conductivity in soils more accurately in the field, including using gravitational methods for saturated soils and the Proportional Cylinder and Arya-Dierolf models for unsaturated soils. It analyzes modifying Darcy's law to account for centrifugal force when measuring saturated soils and how the Proportional Cylinder and Arya-Dierolf models can help determine unsaturated pore size and estimate hydraulic conductivity. Accurately measuring hydraulic conductivity is important for environmental cleanup efforts to more efficiently remove contaminants from lands.
Numerical Investigation of Head Frontal Velocity of Non-conservative Dense Fl...IRJET Journal
This document presents a numerical investigation of the head frontal velocity of non-conservative dense flows in small inclined beds. The study uses the Fluent numerical code to simulate dense flow frontal velocity two-dimensionally using the Euler-Lagrange method. The results from the numerical model show good agreement with experimental results and help analyze fluid movement patterns at different scales. Key findings include that head frontal velocity remains fixed in the numerical and experimental models from 3-11 meters from the inlet, and the Fluent code is suitable for simulating these types of flows when compared to empirical experimental results.
The Philadelphia Inquirer, Philadelphia Daily News, and philly.com hired a PR firm to help a new group of investors relaunch the brands after acquiring them. The PR firm executed an aggressive media relations campaign highlighting the marketing expertise of the new team. This helped gain coverage for the relaunch in local, trade, and national media. As a result, readership grew and web traffic increased significantly. The PR firm also helped launch successful events that brought new readers and revenue.
This document discusses four students - Phoebe, Megan, Tyler, and Alexis - who committed suicide after experiencing cyberbullying. It provides brief biographical information about each student, noting what careers they may have pursued based on their interests. The document also includes links to news coverage about each case, asking the reader to consider what could have been done differently to change the outcomes and assigning a reaction paper on this topic using MLA formatting.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document discusses developing accessibility levels in rural areas of India. It focuses on a study area between Rajam and Srikakulam in Andhra Pradesh, India. Household and onboard surveys were conducted to collect data on trip characteristics, purposes, lengths, and satisfaction levels. Accessibility levels were calculated for activities like work, college etc. based on their weights or importance. Some villages like Palakandyam, Santa Uriti and Reddipeta had poor accessibility levels. Measures to increase accessibility include improving transport facilities to key activities. A travel demand model was developed to forecast future trips up to 2018 based on population growth rates. Costs were estimated for different modes of transport to identify more cost effective options.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
call for paper 2012, hard copy of journal, research paper publishing, where to publish research paper,
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
International Journal of Engineering Research and DevelopmentIJERD Editor
This document summarizes a study on the performance of concrete with granite slab waste used as coarse aggregate at elevated temperatures. Concrete specimens containing either conventional coarse aggregate or granite slab waste aggregate were tested after being heated to temperatures of 2000°C, 4000°C, and 6000°C. The study found that the compressive strength, split tensile strength, flexural strength, and modulus of elasticity of both types of concrete decreased with increasing temperature. However, the granite slab waste concrete generally exhibited greater strength loss. Water-cooled specimens performed better than air-cooled ones due to rehydration, but this effect was less pronounced for the granite slab waste concrete. The study concluded that granite slab waste can be used as a
International Journal of Engineering Research and DevelopmentIJERD Editor
This document describes the simulation and performance evaluation of a wireless ad hoc network using the NS2 simulator. The network uses the AODV routing protocol. 15 nodes were simulated over a 1000m x 800m area for 1000 seconds, with 6 concurrent UDP connections. Packet delivery ratio, throughput, and packet drop ratio were evaluated based on the trace file data. The simulation found a packet delivery ratio of 0.71 and throughput of around 534.19 kbps for the AODV protocol in the simulated network.
International Journal of Engineering Research and DevelopmentIJERD Editor
1. The document compares the compression efficiency of different embedded image compression techniques - Discrete Wavelet Transform (DWT) with Embedded Zero Coding (EZW) and Set Partitioning in Hierarchical Trees (SPIHT) algorithms.
2. It analyzes the performance of EZW and SPIHT algorithms using different wavelet families (biorthogonal, daubechies, coiflets) on the Lena test image. Results show that biorthogonal wavelets like bior4.4 and bior6.8, and daubechies wavelets like db4 and db10 achieved good Peak Signal to Noise Ratio at low bit rates.
3. The document further improves compression by applying H
IJERD(www.ijerd.com)International Journal of Engineering Research and Develop...IJERD Editor
The document summarizes the methodology for creating "magic squares", where the sums of each row, column and diagonal are equal, using successive numbers. It presents two cases - one using odd numbers only and building up the operations, and one using even numbers only. For each case, it provides the general formulas for determining the size of the square and rules for positioning the numbers in the squares based on operations of odd and even numbers. It also includes an example of a 12x12 magic square as a result.
International Journal of Engineering Research and Development (IJERD)IJERD Editor
journal publishing, how to publish research paper, Call For research paper, international journal, publishing a paper, IJERD, journal of science and technology, how to get a research paper published, publishing a paper, publishing of journal, publishing of research paper, reserach and review articles, IJERD Journal, How to publish your research paper, publish research paper, open access engineering journal, Engineering journal, Mathemetics journal, Physics journal, Chemistry journal, Computer Engineering, Computer Science journal, how to submit your paper, peer reviw journal, indexed journal, reserach and review articles, engineering journal, www.ijerd.com, research journals,
yahoo journals, bing journals, International Journal of Engineering Research and Development, google journals, hard copy of journal
Sans Feb 2010 - When Web 2 0 Attacks v3.3Rafal Los
The document discusses security issues related to Web 2.0 technologies. It notes that Web 2.0 has increased the attack surface area by moving more logic to the client-side and allowing richer content. Various attacks are explored like clickjacking, cross-site scripting using social media sites, exploiting functionality in Flash applications, and manipulating client-side logic and data validations. Sensitive information may also be exposed. The document provides examples of real code vulnerabilities and demonstrates live decompiling of Flash to find vulnerabilities. It concludes with an example attack on MapQuest by inserting malicious code.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document discusses optimization and simulation of a creasing machine. It begins with an introduction to creasing machines and the creasing process for corrugated sheets. It then discusses CAD modeling and FEM analysis that was performed on the creasing rollers to identify opportunities to improve the machine. The goal is to optimize the production rate by reducing setup time for different sheet widths. In conclusion, the work focuses on using FEM testing to evaluate failures and help design an improved system with higher production rates per hour.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document discusses the destruction of mangrove forests in the District of Jailolo, West Halmahera Regency, North Maluku Province, Indonesia. The mangrove forests in this area are being rapidly destroyed through the local community's utilization of wood from the mangroves for firewood, building materials, and conversion of mangrove areas to fishponds. This destruction threatens the region's coastal protection, marine life habitats, and livelihoods of local fishermen. The document calls for conservation education programs in local schools to increase awareness of the importance of mangrove forest protection.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
This study evaluated the effectiveness of Ocimum sanctum (Tulsi) and Azadirachta indica (Neem) for disinfecting drinking water sources in rural areas. Aqueous extracts, alcoholic extracts, and fresh leaf juices of Tulsi and Neem were tested against Salmonella typhi bacteria. The alcoholic extracts showed the greatest ability to reduce bacterial counts and most probable number (MPN) of coliforms in well, lake, and river water samples. Specifically, the Neem alcoholic extract reduced MPN from 313 to 0 for well water. While affordable and accessible for rural populations, further studies on taste, odor removal, and combining with other treatments could improve herbal disinfection as
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
This document describes the design of a low power, high speed fully dynamic CMOS latched comparator. It begins with an abstract that outlines the goal of designing a comparator with less sensitivity to delay using a dynamic CMOS latched comparator approach. It then reviews different comparator architectures including open loop, regenerative, and preamplifier-based designs. The focus is on fully dynamic latched comparators, analyzing their advantages and disadvantages. A novel comparator design is proposed that provides better input offset characteristics and faster operation than previous designs like resistor divider, latch-type, and double-tail comparators. The schematic and operating principles of the proposed comparator are described.
International Journal of Engineering Research and DevelopmentIJERD Editor
• Electrical, Electronics and Computer Engineering,
• Information Engineering and Technology,
• Mechanical, Industrial and Manufacturing Engineering,
• Automation and Mechatronics Engineering,
• Material and Chemical Engineering,
• Civil and Architecture Engineering,
• Biotechnology and Bio Engineering,
• Environmental Engineering,
• Petroleum and Mining Engineering,
• Marine and Agriculture engineering,
• Aerospace Engineering.
International Journal of Engineering Research and DevelopmentIJERD Editor
1) The study investigated the effect of aggregate size on the energy dissipation of plain concrete members subjected to static cyclic loading.
2) Testing found that smaller aggregate size (3/8") resulted in less energy dissipation compared to larger sizes (1/2", 3/4"), and gradually increasing loads led to less energy dissipation than constant loads.
3) Measurement of crack propagation using ultrasound found that larger aggregate sizes led to larger cracks under both constant and gradually increasing loads.
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
1) The document proposes a new robust estimator called INAPSAC (Improved N Adjacent Points Sample Consensus) for image analysis tasks like corner detection.
2) An experiment applies INAPSAC, RANSAC, and NAPSAC to corner detection on different image types and compares processing times and number of corners detected.
3) The results show that INAPSAC has faster processing times and detects more corners than RANSAC and NAPSAC, demonstrating that it is more accurate for corner detection than existing methods.
Comparision of flow analysis through a different geometry of flowmeters using...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and TechnologyIJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Comparison of flow analysis of a sudden and gradual change of pipe diameter u...eSAT Journals
Abstract This paper describes an analytical approach to describe the areas where Pipes (used for flow of fluids) are mostly susceptible to damage and tries to visualize the flow behaviour in various geometric conditions of a pipe. Fluent software was used to plot the characteristics of the flow and gambit software was used to design the 2D model. Two phase Computational fluid dynamics calculations, using K-epsilon model were employed. This simulation gives the values of pressure and velocity contours at various sections of the pipe in which water as a media. A comparison was made with the sudden and gradual change of pipe diameter (i.e., expansion and contraction of the pipe). The numerical results were validated against experimental data from the literature and were found to be in good agreement. Index Terms: gambit, fluent software.
Lattice boltzmann simulation of non newtonian fluid flow in a lid driven cavitIAEME Publication
This document summarizes a study that uses Lattice Boltzmann Method (LBM) to simulate non-Newtonian fluid flow in a lid driven cavity. The study explores the mechanism of non-Newtonian fluid flow using the power law model to represent shear-thinning and shear-thickening fluids. It investigates the influence of power law index and Reynolds number on velocity profiles and streamlines. The LBM code is validated against published results and shows agreement with established theory and fluid rheological behavior.
A study on Nonlinear flow through an orifice metersunnynita
The document presents a study on nonlinear flow through orifice meters. It discusses:
- The working principle of orifice meters and factors that cause nonlinear flow
- Governing equations for modeling unsteady nonlinear flow through orifices
- A literature review of past studies on acoustic nonlinearity in orifices and CFD simulations of orifice flow
- Results of simulations showing the relationships between discharge, head, pressure gradient, and Forchheimer number
- Conclusions that the flow is affected by pressure gradient and fluid velocity, and that Forchheimer number is important for modeling nonlinear orifice flow
LATTICE BOLTZMANN SIMULATION OF NON-NEWTONIAN FLUID FLOW IN A LID DRIVEN CAVITY IAEME Publication
Lattice Boltzmann Method (LBM) is used to simulate the lid driven cavity flow to explore the mechanism of non-Newtonian fluid flow. The power law model is used to represent the class of non-Newtonian fluids (shear-thinning and shear-thickening fluids) by considering a range of 0.8 to 1.6. Investigation is carried out to study the influence of power law index and Reynolds number on the variation of velocity profiles and streamlines plots. Velocity profiles and the streamline patterns
for various values of power law index at Reynolds numbers ranging 100 to 3200 are presented. Half way bounce back boundary conditions are employed in the numerical method.
CFD and Artificial Neural Networks Analysis of Plane Sudden Expansion FlowsCSCJournals
It has been clearly established that the reattachment length for laminar flow depends on two non-dimensional parameters, the Reynolds number and the expansion ratio, therefore in this work, an ANN model that predict reattachment positions for the expansion ratios of 2, 3 and 5 based on the above two parameters has been developed. The R2 values of the testing set output Xr1, Xr2, Xr3, and Xr4 were 0.9383, 0.8577, 0.997 and 0.999 respectively. These results indicate that the network model produced reattachment positions that were in close agreement with the actual values. When considering the reattachment length of plane sudden-expansions the judicious combination of CFD calculated solutions with ANN will result in a considerable saving in computing and turnaround time. Thus CFD can be used in the first instance to obtain reattachment lengths for a limited choice of Reynolds numbers and ANN will be used subsequently to predict the reattachment lengths for other intermediate Reynolds number values. The CFD calculations concern unsteady laminar flow through a plane sudden expansion and are performed using a commercial CFD code STAR-CD while the training process of the corresponding ANN model was performed using the NeuroShellTM simulator.
This document describes a numerical study that simulates two-phase flows in C-shaped and U-shaped pipes using a 1D centerline-based mesh generation technique. The study investigates the effects of four different gravitational directions on pressure changes, bubble dynamics, and flow physics. Governing equations for a two-fluid model are presented and solved using the open-source software OpenFOAM. A 1D centerline mesh generation algorithm is used to divide the pipe geometry into cross-sectional zones for control volume analysis. Simulation results show the influence of buoyancy forces on dynamic pressure and turbulent kinetic energy in the two-phase flows.
Comparative Analysis Fully Developed Turbulent Flow in Various Arbitrary Cros...IRJET Journal
This document presents a comparative computational fluid dynamics (CFD) analysis of fully developed turbulent flow in circular, triangular, and rectangular cross-section pipes using the finite volume method. The study examines the flow of water at high Reynolds numbers using the k-ε turbulence model. Contour plots show that triangular duct has the highest dynamic pressure at the outlet, while rectangular duct has higher dynamic pressure than circular duct at the center and outlet. Turbulent intensity graphs indicate intensity increases more significantly after certain distances in circular and triangular ducts, but continuously increases along the rectangular duct length due to less variation in boundary layer and viscous sublayer.
This document summarizes a numerical simulation study of flow past a circular cylinder in a channel at varying ratios of tunnel height to cylinder diameter (H/D). Two computational fluid dynamics codes, 3D PURLES and OpenFOAM, were used to simulate the flow at a Reynolds number of 40. The simulations showed a decrease in wake length and a shift of flow separation downstream at smaller H/D ratios. Grid resolution and H/D ratios from 2-30 were investigated. The results from both codes were consistent and confirmed the effects of tunnel walls in changing flow characteristics around the cylinder.
Computational Analysis of Turbulent flow heat transfer and pressure loss in D...IRJET Journal
This document discusses computational analysis of turbulent flow, heat transfer, and pressure loss in ducts or pipes with segmental baffles. Segmental baffles are implemented to enhance flow characteristics and thermal performance. Due to the baffles, significant turbulence is generated, increasing friction with the pipe and improving heat transfer but also leading to greater pressure drop. Finite element analysis is conducted using ANSYS Fluent to simulate turbulent flow over a range of Reynolds numbers in smooth and baffled pipes. Results are validated against published experimental and numerical data and show good agreement. Contour plots illustrate increased turbulence and velocity magnitude in baffled pipes compared to smooth pipes.
The Effect of Geometry Parameters and Flow Characteristics on Erosion and Sed...Dr. Amarjeet Singh
One of the most critical problems in the river
engineering field is scouring, sedimentation and morphology
of a river bed. In this paper, a finite volume method
FORTRAN code is provided and used. The code is able to
model the sedimentation. The flow and sediment were
modeled at the interception of the two channels. It is applied
an experimental model to evaluate the results. Regarding the
numerical model, the effects of geometry parameters such as
proportion of secondary channel to main channel width and
intersection angle and also hydraulic conditionals like
secondary to main channel discharge ratio and inlet flow
Froude number were studied on bed topographical and flow
pattern. The numerical results show that the maximum
height of bed increased to 32 percent as the discharge ratio
reaches to 51 percent, on average. It is observed that the
maximum height of sedimentation decreases by declining in
main channel to secondary channel Froude number ratio. On
the assessment of the channel width, velocity and final bed
height variations have changed by given trend, in all the
ratios. Also, increasing in the intersection angle accompanied
by decreasing in flow velocity variations along the channel.
The pattern of velocity and topographical bed variations are
also constant in any studied angles.
A Computational Investigation of Flow Structure Within a Sinuous DuctIJERA Editor
In the present investigation the distribution of mean velocity are experimentally studied on three constant area
rectangular curved ducts with an aspect ratio of 2.4. First one is C-shape, second one is S-shape and third one
is a DS-shape duct. The experiment is carried out at mass averaged mean velocity of 40m/s for all the ducts.
The velocity distribution shows for C-duct, the bulk flow shifting from outer wall to the inner wall along the
flow passage and for S-duct, the bulk flow shifting from outer wall to the inner wall in the first half and from
inner wall to the outer wall in the second half along the flow passage of curved ducts are very instinct. Due to
the imbalance of centrifugal force and radial pressure gradient, secondary motions in the forms of counter
rotating vortices have been generated within both the curved duct. For DS-duct the velocity distributions shows
the Bulk of flow shifting from inner watt to outer wall in the first bend and third bend of the duct and outer wall
to inner wall in the second bend and forth bend of the duct along the flow passage is very instinct. Flow at end
of the DS-duct is purely uniform in nature due to non existence of secondary motion. The experimental results
then were numerically validated with the help of Fluent, which shows a good agreement between the
experimental and predicted results for all the ducts
This document summarizes a research study that investigated how modifications to a river's physical specifications, like width and length, impact the coefficients of the Muskingum flood routing model. The researchers used a genetic algorithm to compute the nonlinear Muskingum model coefficients after altering the river width and length in their schematic model. They found a logical relationship between changes in the river characteristics and the model coefficients. The goal was to determine if a mathematical relationship could be derived to express how modifications to the physical properties affect the coefficients.
Numerical Analysis of MHD Flow of Fluid with One Porous Bounding WallIRJET Journal
1. The document analyzes the laminar flow of a viscous, incompressible fluid between two parallel plates, where one plate is porous and the other is rigid.
2. It develops governing equations for the fluid flow using the Navier-Stokes equations and introduces dimensionless variables and a perturbation method.
3. It presents results showing that increasing the magnetic field increases the fluid velocity, while increasing the channel height decreases the velocity at a constant Reynolds number and slip coefficient. Graphs demonstrate how the fluid velocity profiles vary with changing magnetic field.
Bifurcation phonomena in viscoelastic flowsgerardoimanuel
This document summarizes a numerical study of viscoelastic fluid flow through a 1:4 planar sudden expansion. The study investigates both Newtonian and viscoelastic fluid flow using the FENE-MCR constitutive model. For Newtonian fluids, above a critical Reynolds number of around 36, the flow exhibits a stable asymmetric state downstream of the expansion. For viscoelastic fluids, elastic effects were found to stabilize the flow, allowing symmetric flow at higher Reynolds numbers. The study systematically varies parameters like the Reynolds number, Weissenberg number, and solvent viscosity ratio to analyze their effects on the flow field, vortex structures, and pressure and velocity profiles.
Groundwater Quality Modelling using Coupled Galerkin Finite Element and Modif...AM Publications
This paper presents a coupled Galerkin finite element model for groundwater flow simulation (FEFLOW)
and Modified Method of Characteristics model for the simulation of solute transport (MMOCSOLUTE) in twodimensional,
transient, unconfined groundwater flow systems. The coupling factor is velocity field which is simulated
by finite element technique. The study mainly focuses on groundwater quality aspects hence the flow simulation
model has been kept conventional whereas the solute transport model is improvised by approximating dispersion term.
This coupled model is used to obtain the space and time distribution of head and concentration for the reported
synthetic test case. Further the sensitivity of model results to variation in parameters viz. porosity, dispersivity and
combined injection and pumping rates is analyzed. The model results are compared with the reported solutions of the
model presented by Chiang et al. (1989).
The document summarizes a numerical study of laminar flow through concentric circular pipes. The study examines developing flow in the entrance region of the main pipe and inside the disturbed pipe, where a non-uniform flow develops in the annular region around the disturbed pipe. Numerical solutions were obtained for a range of Reynolds numbers from 25 to 375 using a computer program and AutoFEA software to calculate velocity and pressure fields. Results showed the boundary layer developed faster at lower Reynolds numbers, while flow patterns were similar across cases. Findings agreed well with the AutoFEA software.
1) The document describes simulations of fluid flow through pipes with sudden expansions and contractions using ANSYS.
2) Three turbulence models (k-epsilon, RSM-omega, and SST k-omega) were used to simulate the flows and compare results.
3) Key results like pressure drop, velocity profiles, and turbulent intensities were compared between the models for both the sudden expansion and contraction geometries.
This project aims at simulating lid driven cavity flow problem using package MATLAB. Steady Incompressible Navier-Stokes equation with continuity equation will be studied at various Reynolds number. The main aim is to obtain the velocity field in steady state using the finite difference formulation on momentum equations and continuity equation. Reynold number is the pertinent parameter of the present study. Taylor’s series expansion has been used to convert the governing equations in the algebraic form using finite difference schemes.
Similar to IJERD(www.ijerd.com)International Journal of Engineering Research and Development (20)
A Novel Method for Prevention of Bandwidth Distributed Denial of Service AttacksIJERD Editor
Distributed Denial of Service (DDoS) Attacks became a massive threat to the Internet. Traditional
Architecture of internet is vulnerable to the attacks like DDoS. Attacker primarily acquire his army of Zombies,
then that army will be instructed by the Attacker that when to start an attack and on whom the attack should be
done. In this paper, different techniques which are used to perform DDoS Attacks, Tools that were used to
perform Attacks and Countermeasures in order to detect the attackers and eliminate the Bandwidth Distributed
Denial of Service attacks (B-DDoS) are reviewed. DDoS Attacks were done by using various Flooding
techniques which are used in DDoS attack.
The main purpose of this paper is to design an architecture which can reduce the Bandwidth
Distributed Denial of service Attack and make the victim site or server available for the normal users by
eliminating the zombie machines. Our Primary focus of this paper is to dispute how normal machines are
turning into zombies (Bots), how attack is been initiated, DDoS attack procedure and how an organization can
save their server from being a DDoS victim. In order to present this we implemented a simulated environment
with Cisco switches, Routers, Firewall, some virtual machines and some Attack tools to display a real DDoS
attack. By using Time scheduling, Resource Limiting, System log, Access Control List and some Modular
policy Framework we stopped the attack and identified the Attacker (Bot) machines
Hearing loss is one of the most common human impairments. It is estimated that by year 2015 more
than 700 million people will suffer mild deafness. Most can be helped by hearing aid devices depending on the
severity of their hearing loss. This paper describes the implementation and characterization details of a dual
channel transmitter front end (TFE) for digital hearing aid (DHA) applications that use novel micro
electromechanical- systems (MEMS) audio transducers and ultra-low power-scalable analog-to-digital
converters (ADCs), which enable a very-low form factor, energy-efficient implementation for next-generation
DHA. The contribution of the design is the implementation of the dual channel MEMS microphones and powerscalable
ADC system.
Influence of tensile behaviour of slab on the structural Behaviour of shear c...IJERD Editor
-A composite beam is composed of a steel beam and a slab connected by means of shear connectors
like studs installed on the top flange of the steel beam to form a structure behaving monolithically. This study
analyzes the effects of the tensile behavior of the slab on the structural behavior of the shear connection like slip
stiffness and maximum shear force in composite beams subjected to hogging moment. The results show that the
shear studs located in the crack-concentration zones due to large hogging moments sustain significantly smaller
shear force and slip stiffness than the other zones. Moreover, the reduction of the slip stiffness in the shear
connection appears also to be closely related to the change in the tensile strain of rebar according to the increase
of the load. Further experimental and analytical studies shall be conducted considering variables such as the
reinforcement ratio and the arrangement of shear connectors to achieve efficient design of the shear connection
in composite beams subjected to hogging moment.
Gold prospecting using Remote Sensing ‘A case study of Sudan’IJERD Editor
Gold has been extracted from northeast Africa for more than 5000 years, and this may be the first
place where the metal was extracted. The Arabian-Nubian Shield (ANS) is an exposure of Precambrian
crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. ANS
includes the nations of Israel, Jordan. Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia.
Arabian Nubian Shield Consists of juvenile continental crest that formed between 900 550 Ma, when intra
oceanic arc welded together along ophiolite decorated arc. Primary Au mineralization probably developed in
association with the growth of intra oceanic arc and evolution of back arc. Multiple episodes of deformation
have obscured the primary metallogenic setting, but at least some of the deposits preserve evidence that they
originate as sea floor massive sulphide deposits.
The Red Sea Hills Region is a vast span of rugged, harsh and inhospitable sector of the Earth with
inimical moon-like terrain, nevertheless since ancient times it is famed to be an abode of gold and was a major
source of wealth for the Pharaohs of ancient Egypt. The Pharaohs old workings have been periodically
rediscovered through time. Recent endeavours by the Geological Research Authority of Sudan led to the
discovery of a score of occurrences with gold and massive sulphide mineralizations. In the nineties of the
previous century the Geological Research Authority of Sudan (GRAS) in cooperation with BRGM utilized
satellite data of Landsat TM using spectral ratio technique to map possible mineralized zones in the Red Sea
Hills of Sudan. The outcome of the study mapped a gossan type gold mineralization. Band ratio technique was
applied to Arbaat area and a signature of alteration zone was detected. The alteration zones are commonly
associated with mineralization. The alteration zones are commonly associated with mineralization. A filed check
confirmed the existence of stock work of gold bearing quartz in the alteration zone. Another type of gold
mineralization that was discovered using remote sensing is the gold associated with metachert in the Atmur
Desert.
Reducing Corrosion Rate by Welding DesignIJERD Editor
This document summarizes a study on reducing corrosion rates in steel through welding design. The researchers tested different welding groove designs (X, V, 1/2X, 1/2V) and preheating temperatures (400°C, 500°C, 600°C) on ferritic malleable iron samples. Testing found that X and V groove designs with 500°C and 600°C preheating had corrosion rates of 0.5-0.69% weight loss after 14 days, compared to 0.57-0.76% for 400°C preheating. Higher preheating reduced residual stresses which decreased corrosion. Residual stresses were 1.7 MPa for optimal X groove and 600°C
Router 1X3 – RTL Design and VerificationIJERD Editor
Routing is the process of moving a packet of data from source to destination and enables messages
to pass from one computer to another and eventually reach the target machine. A router is a networking device
that forwards data packets between computer networks. It is connected to two or more data lines from different
networks (as opposed to a network switch, which connects data lines from one single network). This paper,
mainly emphasizes upon the study of router device, it‟s top level architecture, and how various sub-modules of
router i.e. Register, FIFO, FSM and Synchronizer are synthesized, and simulated and finally connected to its top
module.
Active Power Exchange in Distributed Power-Flow Controller (DPFC) At Third Ha...IJERD Editor
This paper presents a component within the flexible ac-transmission system (FACTS) family, called
distributed power-flow controller (DPFC). The DPFC is derived from the unified power-flow controller (UPFC)
with an eliminated common dc link. The DPFC has the same control capabilities as the UPFC, which comprise
the adjustment of the line impedance, the transmission angle, and the bus voltage. The active power exchange
between the shunt and series converters, which is through the common dc link in the UPFC, is now through the
transmission lines at the third-harmonic frequency. DPFC multiple small-size single-phase converters which
reduces the cost of equipment, no voltage isolation between phases, increases redundancy and there by
reliability increases. The principle and analysis of the DPFC are presented in this paper and the corresponding
simulation results that are carried out on a scaled prototype are also shown.
Mitigation of Voltage Sag/Swell with Fuzzy Control Reduced Rating DVRIJERD Editor
Power quality has been an issue that is becoming increasingly pivotal in industrial electricity
consumers point of view in recent times. Modern industries employ Sensitive power electronic equipments,
control devices and non-linear loads as part of automated processes to increase energy efficiency and
productivity. Voltage disturbances are the most common power quality problem due to this the use of a large
numbers of sophisticated and sensitive electronic equipment in industrial systems is increased. This paper
discusses the design and simulation of dynamic voltage restorer for improvement of power quality and
reduce the harmonics distortion of sensitive loads. Power quality problem is occurring at non-standard
voltage, current and frequency. Electronic devices are very sensitive loads. In power system voltage sag,
swell, flicker and harmonics are some of the problem to the sensitive load. The compensation capability
of a DVR depends primarily on the maximum voltage injection ability and the amount of stored
energy available within the restorer. This device is connected in series with the distribution feeder at
medium voltage. A fuzzy logic control is used to produce the gate pulses for control circuit of DVR and the
circuit is simulated by using MATLAB/SIMULINK software.
Study on the Fused Deposition Modelling In Additive ManufacturingIJERD Editor
Additive manufacturing process, also popularly known as 3-D printing, is a process where a product
is created in a succession of layers. It is based on a novel materials incremental manufacturing philosophy.
Unlike conventional manufacturing processes where material is removed from a given work price to derive the
final shape of a product, 3-D printing develops the product from scratch thus obviating the necessity to cut away
materials. This prevents wastage of raw materials. Commonly used raw materials for the process are ABS
plastic, PLA and nylon. Recently the use of gold, bronze and wood has also been implemented. The complexity
factor of this process is 0% as in any object of any shape and size can be manufactured.
Spyware triggering system by particular string valueIJERD Editor
This computer programme can be used for good and bad purpose in hacking or in any general
purpose. We can say it is next step for hacking techniques such as keylogger and spyware. Once in this system if
user or hacker store particular string as a input after that software continually compare typing activity of user
with that stored string and if it is match then launch spyware programme.
A Blind Steganalysis on JPEG Gray Level Image Based on Statistical Features a...IJERD Editor
This paper presents a blind steganalysis technique to effectively attack the JPEG steganographic
schemes i.e. Jsteg, F5, Outguess and DWT Based. The proposed method exploits the correlations between
block-DCTcoefficients from intra-block and inter-block relation and the statistical moments of characteristic
functions of the test image is selected as features. The features are extracted from the BDCT JPEG 2-array.
Support Vector Machine with cross-validation is implemented for the classification.The proposed scheme gives
improved outcome in attacking.
Secure Image Transmission for Cloud Storage System Using Hybrid SchemeIJERD Editor
- Data over the cloud is transferred or transmitted between servers and users. Privacy of that
data is very important as it belongs to personal information. If data get hacked by the hacker, can be
used to defame a person’s social data. Sometimes delay are held during data transmission. i.e. Mobile
communication, bandwidth is low. Hence compression algorithms are proposed for fast and efficient
transmission, encryption is used for security purposes and blurring is used by providing additional
layers of security. These algorithms are hybridized for having a robust and efficient security and
transmission over cloud storage system.
Application of Buckley-Leverett Equation in Modeling the Radius of Invasion i...IJERD Editor
A thorough review of existing literature indicates that the Buckley-Leverett equation only analyzes
waterflood practices directly without any adjustments on real reservoir scenarios. By doing so, quite a number
of errors are introduced into these analyses. Also, for most waterflood scenarios, a radial investigation is more
appropriate than a simplified linear system. This study investigates the adoption of the Buckley-Leverett
equation to estimate the radius invasion of the displacing fluid during waterflooding. The model is also adopted
for a Microbial flood and a comparative analysis is conducted for both waterflooding and microbial flooding.
Results shown from the analysis doesn’t only records a success in determining the radial distance of the leading
edge of water during the flooding process, but also gives a clearer understanding of the applicability of
microbes to enhance oil production through in-situ production of bio-products like bio surfactans, biogenic
gases, bio acids etc.
Gesture Gaming on the World Wide Web Using an Ordinary Web CameraIJERD Editor
- Gesture gaming is a method by which users having a laptop/pc/x-box play games using natural or
bodily gestures. This paper presents a way of playing free flash games on the internet using an ordinary webcam
with the help of open source technologies. Emphasis in human activity recognition is given on the pose
estimation and the consistency in the pose of the player. These are estimated with the help of an ordinary web
camera having different resolutions from VGA to 20mps. Our work involved giving a 10 second documentary to
the user on how to play a particular game using gestures and what are the various kinds of gestures that can be
performed in front of the system. The initial inputs of the RGB values for the gesture component is obtained by
instructing the user to place his component in a red box in about 10 seconds after the short documentary before
the game is finished. Later the system opens the concerned game on the internet on popular flash game sites like
miniclip, games arcade, GameStop etc and loads the game clicking at various places and brings the state to a
place where the user is to perform only gestures to start playing the game. At any point of time the user can call
off the game by hitting the esc key and the program will release all of the controls and return to the desktop. It
was noted that the results obtained using an ordinary webcam matched that of the Kinect and the users could
relive the gaming experience of the free flash games on the net. Therefore effective in game advertising could
also be achieved thus resulting in a disruptive growth to the advertising firms.
Hardware Analysis of Resonant Frequency Converter Using Isolated Circuits And...IJERD Editor
-LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region[5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits.
Simulated Analysis of Resonant Frequency Converter Using Different Tank Circu...IJERD Editor
LLC resonant frequency converter is basically a combo of series as well as parallel resonant ckt. For
LCC resonant converter it is associated with a disadvantage that, though it has two resonant frequencies, the
lower resonant frequency is in ZCS region [5]. For this application, we are not able to design the converter
working at this resonant frequency. LLC resonant converter existed for a very long time but because of
unknown characteristic of this converter it was used as a series resonant converter with basically a passive
(resistive) load. . Here, it was designed to operate in switching frequency higher than resonant frequency of the
series resonant tank of Lr and Cr converter acts very similar to Series Resonant Converter. The benefit of LLC
resonant converter is narrow switching frequency range with light load[6] . Basically, the control ckt plays a
very imp. role and hence 555 Timer used here provides a perfect square wave as the control ckt provides no
slew rate which makes the square wave really strong and impenetrable. The dead band circuit provides the
exclusive dead band in micro seconds so as to avoid the simultaneous firing of two pairs of IGBT’s where one
pair switches off and the other on for a slightest period of time. Hence, the isolator ckt here is associated with
each and every ckt used because it acts as a driver and an isolation to each of the IGBT is provided with one
exclusive transformer supply[3]. The IGBT’s are fired using the appropriate signal using the previous boards
and hence at last a high frequency rectifier ckt with a filtering capacitor is used to get an exact dc
waveform .The basic goal of this particular analysis is to observe the wave forms and characteristics of
converters with differently positioned passive elements in the form of tank circuits. The supported simulation
is done through PSIM 6.0 software tool
Amateurs Radio operator, also known as HAM communicates with other HAMs through Radio
waves. Wireless communication in which Moon is used as natural satellite is called Moon-bounce or EME
(Earth -Moon-Earth) technique. Long distance communication (DXing) using Very High Frequency (VHF)
operated amateur HAM radio was difficult. Even with the modest setup having good transceiver, power
amplifier and high gain antenna with high directivity, VHF DXing is possible. Generally 2X11 YAGI antenna
along with rotor to set horizontal and vertical angle is used. Moon tracking software gives exact location,
visibility of Moon at both the stations and other vital data to acquire real time position of moon.
“MS-Extractor: An Innovative Approach to Extract Microsatellites on „Y‟ Chrom...IJERD Editor
Simple Sequence Repeats (SSR), also known as Microsatellites, have been extensively used as
molecular markers due to their abundance and high degree of polymorphism. The nucleotide sequences of
polymorphic forms of the same gene should be 99.9% identical. So, Microsatellites extraction from the Gene is
crucial. However, Microsatellites repeat count is compared, if they differ largely, he has some disorder. The Y
chromosome likely contains 50 to 60 genes that provide instructions for making proteins. Because only males
have the Y chromosome, the genes on this chromosome tend to be involved in male sex determination and
development. Several Microsatellite Extractors exist and they fail to extract microsatellites on large data sets of
giga bytes and tera bytes in size. The proposed tool “MS-Extractor: An Innovative Approach to extract
Microsatellites on „Y‟ Chromosome” can extract both Perfect as well as Imperfect Microsatellites from large
data sets of human genome „Y‟. The proposed system uses string matching with sliding window approach to
locate Microsatellites and extracts them.
Importance of Measurements in Smart GridIJERD Editor
- The need to get reliable supply, independence from fossil fuels, and capability to provide clean
energy at a fixed and lower cost, the existing power grid structure is transforming into Smart Grid. The
development of a smart energy distribution grid is a current goal of many nations. A Smart Grid should have
new capabilities such as self-healing, high reliability, energy management, and real-time pricing. This new era
of smart future grid will lead to major changes in existing technologies at generation, transmission and
distribution levels. The incorporation of renewable energy resources and distribution generators in the existing
grid will increase the complexity, optimization problems and instability of the system. This will lead to a
paradigm shift in the instrumentation and control requirements for Smart Grids for high quality, stable and
reliable electricity supply of power. The monitoring of the grid system state and stability relies on the
availability of reliable measurement of data. In this paper the measurement areas that highlight new
measurement challenges, development of the Smart Meters and the critical parameters of electric energy to be
monitored for improving the reliability of power systems has been discussed.
Study of Macro level Properties of SCC using GGBS and Lime stone powderIJERD Editor
The document summarizes a study on the use of ground granulated blast furnace slag (GGBS) and limestone powder to replace cement in self-compacting concrete (SCC). Tests were conducted on SCC mixes with 0-50% replacement of cement with GGBS and 0-20% replacement with limestone powder. The results showed that replacing 30% of cement with GGBS and 15% with limestone powder produced SCC with the highest compressive strength of 46MPa, meeting fresh property requirements. The study concluded that this ternary blend of cement, GGBS and limestone powder can improve SCC properties while reducing costs.
Leveraging AI for Software Developer Productivity.pptxpetabridge
Supercharge your software development productivity with our latest webinar! Discover the powerful capabilities of AI tools like GitHub Copilot and ChatGPT 4.X. We'll show you how these tools can automate tedious tasks, generate complete syntax, and enhance code documentation and debugging.
In this talk, you'll learn how to:
- Efficiently create GitHub Actions scripts
- Convert shell scripts
- Develop Roslyn Analyzers
- Visualize code with Mermaid diagrams
And these are just a few examples from a vast universe of possibilities!
Packed with practical examples and demos, this presentation offers invaluable insights into optimizing your development process. Don't miss the opportunity to improve your coding efficiency and productivity with AI-driven solutions.
Brightwell ILC Futures workshop David Sinclair presentationILC- UK
As part of our futures focused project with Brightwell we organised a workshop involving thought leaders and experts which was held in April 2024. Introducing the session David Sinclair gave the attached presentation.
For the project we want to:
- explore how technology and innovation will drive the way we live
- look at how we ourselves will change e.g families; digital exclusion
What we then want to do is use this to highlight how services in the future may need to adapt.
e.g. If we are all online in 20 years, will we need to offer telephone-based services. And if we aren’t offering telephone services what will the alternative be?
Test Management as Chapter 5 of ISTQB Foundation. Topics covered are Test Organization, Test Planning and Estimation, Test Monitoring and Control, Test Execution Schedule, Test Strategy, Risk Management, Defect Management
QA or the Highway - Component Testing: Bridging the gap between frontend appl...zjhamm304
These are the slides for the presentation, "Component Testing: Bridging the gap between frontend applications" that was presented at QA or the Highway 2024 in Columbus, OH by Zachary Hamm.
CNSCon 2024 Lightning Talk: Don’t Make Me Impersonate My IdentityCynthia Thomas
Identities are a crucial part of running workloads on Kubernetes. How do you ensure Pods can securely access Cloud resources? In this lightning talk, you will learn how large Cloud providers work together to share Identity Provider responsibilities in order to federate identities in multi-cloud environments.
MongoDB vs ScyllaDB: Tractian’s Experience with Real-Time MLScyllaDB
Tractian, an AI-driven industrial monitoring company, recently discovered that their real-time ML environment needed to handle a tenfold increase in data throughput. In this session, JP Voltani (Head of Engineering at Tractian), details why and how they moved to ScyllaDB to scale their data pipeline for this challenge. JP compares ScyllaDB, MongoDB, and PostgreSQL, evaluating their data models, query languages, sharding and replication, and benchmark results. Attendees will gain practical insights into the MongoDB to ScyllaDB migration process, including challenges, lessons learned, and the impact on product performance.
CTO Insights: Steering a High-Stakes Database MigrationScyllaDB
In migrating a massive, business-critical database, the Chief Technology Officer's (CTO) perspective is crucial. This endeavor requires meticulous planning, risk assessment, and a structured approach to ensure minimal disruption and maximum data integrity during the transition. The CTO's role involves overseeing technical strategies, evaluating the impact on operations, ensuring data security, and coordinating with relevant teams to execute a seamless migration while mitigating potential risks. The focus is on maintaining continuity, optimising performance, and safeguarding the business's essential data throughout the migration process
The document discusses fundamentals of software testing including definitions of testing, why testing is necessary, seven testing principles, and the test process. It describes the test process as consisting of test planning, monitoring and control, analysis, design, implementation, execution, and completion. It also outlines the typical work products created during each phase of the test process.
Database Management Myths for DevelopersJohn Sterrett
Myths, Mistakes, and Lessons learned about Managing SQL Server databases. We also focus on automating and validating your critical database management tasks.
In our second session, we shall learn all about the main features and fundamentals of UiPath Studio that enable us to use the building blocks for any automation project.
📕 Detailed agenda:
Variables and Datatypes
Workflow Layouts
Arguments
Control Flows and Loops
Conditional Statements
💻 Extra training through UiPath Academy:
Variables, Constants, and Arguments in Studio
Control Flow in Studio
Lee Barnes - Path to Becoming an Effective Test Automation Engineer.pdfleebarnesutopia
So… you want to become a Test Automation Engineer (or hire and develop one)? While there’s quite a bit of information available about important technical and tool skills to master, there’s not enough discussion around the path to becoming an effective Test Automation Engineer that knows how to add VALUE. In my experience this had led to a proliferation of engineers who are proficient with tools and building frameworks but have skill and knowledge gaps, especially in software testing, that reduce the value they deliver with test automation.
In this talk, Lee will share his lessons learned from over 30 years of working with, and mentoring, hundreds of Test Automation Engineers. Whether you’re looking to get started in test automation or just want to improve your trade, this talk will give you a solid foundation and roadmap for ensuring your test automation efforts continuously add value. This talk is equally valuable for both aspiring Test Automation Engineers and those managing them! All attendees will take away a set of key foundational knowledge and a high-level learning path for leveling up test automation skills and ensuring they add value to their organizations.
Move Auth, Policy, and Resilience to the PlatformChristian Posta
Developer's time is the most crucial resource in an enterprise IT organization. Too much time is spent on undifferentiated heavy lifting and in the world of APIs and microservices much of that is spent on non-functional, cross-cutting networking requirements like security, observability, and resilience.
As organizations reconcile their DevOps practices into Platform Engineering, tools like Istio help alleviate developer pain. In this talk we dig into what that pain looks like, how much it costs, and how Istio has solved these concerns by examining three real-life use cases. As this space continues to emerge, and innovation has not slowed, we will also discuss the recently announced Istio sidecar-less mode which significantly reduces the hurdles to adopt Istio within Kubernetes or outside Kubernetes.
TrustArc Webinar - Your Guide for Smooth Cross-Border Data Transfers and Glob...TrustArc
Global data transfers can be tricky due to different regulations and individual protections in each country. Sharing data with vendors has become such a normal part of business operations that some may not even realize they’re conducting a cross-border data transfer!
The Global CBPR Forum launched the new Global Cross-Border Privacy Rules framework in May 2024 to ensure that privacy compliance and regulatory differences across participating jurisdictions do not block a business's ability to deliver its products and services worldwide.
To benefit consumers and businesses, Global CBPRs promote trust and accountability while moving toward a future where consumer privacy is honored and data can be transferred responsibly across borders.
This webinar will review:
- What is a data transfer and its related risks
- How to manage and mitigate your data transfer risks
- How do different data transfer mechanisms like the EU-US DPF and Global CBPR benefit your business globally
- Globally what are the cross-border data transfer regulations and guidelines
Elasticity vs. State? Exploring Kafka Streams Cassandra State StoreScyllaDB
kafka-streams-cassandra-state-store' is a drop-in Kafka Streams State Store implementation that persists data to Apache Cassandra.
By moving the state to an external datastore the stateful streams app (from a deployment point of view) effectively becomes stateless. This greatly improves elasticity and allows for fluent CI/CD (rolling upgrades, security patching, pod eviction, ...).
It also can also help to reduce failure recovery and rebalancing downtimes, with demos showing sporty 100ms rebalancing downtimes for your stateful Kafka Streams application, no matter the size of the application’s state.
As a bonus accessing Cassandra State Stores via 'Interactive Queries' (e.g. exposing via REST API) is simple and efficient since there's no need for an RPC layer proxying and fanning out requests to all instances of your streams application.
EverHost AI Review: Empowering Websites with Limitless Possibilities through ...SOFTTECHHUB
The success of an online business hinges on the performance and reliability of its website. As more and more entrepreneurs and small businesses venture into the virtual realm, the need for a robust and cost-effective hosting solution has become paramount. Enter EverHost AI, a revolutionary hosting platform that harnesses the power of "AMD EPYC™ CPUs" technology to provide a seamless and unparalleled web hosting experience.
EverHost AI Review: Empowering Websites with Limitless Possibilities through ...
IJERD(www.ijerd.com)International Journal of Engineering Research and Development
1. International Journal of Engineering Research and Development
ISSN: 2278-067X, Volume 1, Issue 12 (July 2012), PP. 01-09
www.ijerd.com
Investigation of Newtonian Fluid Flow through a Two-
dimensional Sudden Expansion and Sudden Contraction Flow
Passage
Sudipta Ray, Nirmalendu Biswas, Prokash C. Roy
Department of Mechanical Engineering, Jadavpur University, Kolkata – 700 032, India
Abstract––The importance of flow through sudden change in flow passages lies in the numerous industrial applications
such as, polymer processing, injection molding, biomedical instruments, extrusion, thermoforming etc. In this work, fluid
flow through an axi-symmetric sudden contraction flow passages has been carried out using commercial CFD tools.
Flow in the inverse direction, which represents flow through a sudden expansion, has also been simulated for the same
conditions. A comparison has been established between the two flows occurring in the opposite direction. A two-
dimensional computational domain has been chosen for the analysis considering steady, laminar flow and Newtonian
fluid. The effects of flow rates are investigated with constant diameter ratios to understand the flow characteristics for
sudden expansion and sudden contraction geometry. The size of the recirculation zone, flow reattachment length,
redevelopment of flow, recirculating flow strength depends on several parameters, primarily on flow rate i.e. Reynolds
number, expansion/contraction ratio and flow direction. Flow tends to become unstable at lower Reynolds number for
high expansion ratio.
Keywords––Sudden Contraction, Sudden expansion, Recirculation, Flow Separation, Flow Reattachment.
I. INTRODUCTION
The flow of a fluid through a channel having a section, where sudden contraction or sudden expansion of the
geometry takes place is encountered in many engineering applications such as tubular heat exchangers, capillary-tube
viscometry, polymer processing, biomedical instruments, thermoforming, various manufacturing processes, fiber spinning,
extrusion, injection molding, biomedical instruments, flow of refrigerant, etc. Thus, the behavior of flow field in the
presence of sudden expansion geometry has been regarded as one of the most fundamental phenomenon of study in the field
of fluid mechanics. Also due to the relative simplicity and economical feasibility, it is possible to conduct extensive
numerical and experimental studies on the subject. With the presence of various dissipative behaviors such as boundary layer
separation, recirculation, flow redevelopment, etc. flow through abrupt change in flow geometry requires extensive research.
Although, the behavior of the various types of Newtonian and non-Newtonian fluids through the geometry of
sudden contraction has been studied in many ways, till now contraction flow presents some unresolved issues from
fundamental point of view. Hence the need is felt to investigate the contraction flow characteristics with the variation of
different flow parameters. Astarita and Greco [1] studied the excess pressure drop through contraction geometry with the
help of experimental and analytical approaches. Their work contributes to the Hagenbach and Couette correction for the
pressure loss correlations. Christiansen et al. [2] have reported the numerical work of flow through combinations of stream
tube-real tube and real tube-real tube contractions. They presented the radial and axial-velocity profiles at the contraction
region for various Reynolds number (Re). Numerical study of a fluid flowing into a circular tube from a reservoir has been
reported by Vrentas and Duda [3]. Their work does not include the three general assumptions of zero excess viscous pressure
dissipation, uniform velocity profile at inlet and the use of the parabolic, asymptotic form of the flow governing equations to
describe the flow. They found the flow behaviors reach asymptotic nature at Re=200 and CR=4. The work suggests the
absence of vena-contracta at these ranges of the parameters. Experimental and simultaneous numerical work has been
presented in the study of Durst and Loy [4]. Using LDA measurement technique, they measured axial and cross-velocity
components to study the velocity profiles at various axial locations as well as the size of the two separation zones at the
convex and concave corners of the geometry. Their study also provides finite-difference computations using non-uniform
grids. As their experiment was one of the earliest used optical methods in these fields, the authors encountered few
measurement uncertainties and suggested corrective measures for future works.
Mitsoulis and Vlachpoulos [5] applied finite-element method for the solution of the Navier-Stokes equations in a
sudden contraction geometry. Divergence of the residuals for the numerical model was found after a certain Re and radius
ratio. Ozalp et al. [6] have performed flow visualization experiment of flow through a vertical sudden contraction with a
fixed Contraction Ratio, CR=4 by using Particle Image Velocimetry (PIV) technique. They observed the stream-wise and
span-wise velocity contours, for different Re, at the upstream of the contraction just before the abrupt change in geometry
takes place. Chiang et al. [7] applied the primitive variable formulation over the Stream function- Vorticity approach. In
their 3D contraction geometry, they found the existence of symmetry-breaking bifurcations corresponding to the downstream
separation zones at very high Re. Some of the other relevant works on contraction flow deal with flow of non-Newtonian
fluids [8-10] and multiphase fluids [11-15] have been reported. Also, work considering sudden expansion flow geometry
both numerically and experimentally has been reported [16-19].
1
2. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
Although, the behavior of flow through a sudden change in flow passages has been studied extensively in the past
few decades as to observe the separation and other phenomenon associated with it, the study of the previous works reveals
that most of the works has been done in the turbulent region of the flow regime. The various aspects of flow in the laminar
and the critical zone are still in need of more study. Also proper flow distribution in the sudden contraction or sudden
expansion geometry is essential to achieve the desired flow characteristics. Hence the need is to investigate the sudden
contraction and or sudden expansion flow characteristics with the variation of wide range of flow properties and geometric
parameters. It is observed that the formation of separation eddy at the corner of upstream section of the conduit as well as the
accelerated flow at the contraction zone are some of the characteristics of this type of flow. Also, for the same channel
configuration, if the flow direction is reversed, it becomes a case of a flow through a sudden expansion. The study attempts
to compare the flow situations in these two cases.
II. GOVERNING EQUATIONS AND NUMERICAL METHODS:
The geometric configuration of the two-dimensional flow passage is shown in Fig. 1. In case of contraction flow
geometry, fluid flows axially through the inlet passage of width D and then passes through the sudden contraction zone of
width d. The passage is vertically placed with its inlet at the top, thus the major driving force for the flow is gravity. The
Contraction Ratio (CR=β=D/d) is defined as the ratio of the upstream passage width to downstream passage width. For the
cases of expansion, where the flow direction is reversed through the passage, the Expansion ratio has been defined as above.
The passage length for width D and d have been chosen as lD= 12D and ld= 3D respectively. The contraction ratio for the
geometry varies as β=D/d=2, 4 and 8. Similarly, for the case of expansion flow, the expansion ratio values have been chosen
as that of the CR values in the study of the contraction. Also, the channel with length lD, works as the upstream channel for
the contraction flow. It becomes the downstream channel for the expansion flow.
Fig. 1: Computational Domain of Flow Geometry
The boundary conditions considered for the numerical solution are uniform velocity at inlet, normal to the inlet
boundary; due to the large length of the downstream passage, strong one-directional flow situation has been considered at
outlet, thereby specifying the outflow boundary condition. No-slip boundary condition is taken on the walls. The flow is
assumed to be steady, incompressible, Newtonian, isothermal, axisymmetric and laminar. The conservation form of
governing equations for continuity and momentum for the steady flow field are given below.
( U ) ( V ) 0 (1)
x y
p 2U 2U
( U 2 ) ( UV ) ( 2 2 ) (2)
x x x x y
p 2V 2V
( UV ) ( V 2 ) ( 2 2 ) (3)
x x y x y
The numerical simulation has been carried out using commercial CFD tools. The basis of the numerical
simulations follows the finite-volume scheme, with a steady implicit solver; whereas the Power Law model as described by
Patankar [15] has been used for the discretization of the momentum, the standard scheme for pressure and the SIMPLE
algorithm has been applied for the pressure-velocity coupling. The gradient calculation for the flow field has been carried out
using the Green-Gauss Cell-based method. The simulations have been carried out using a convergence criterion of 10-7 for
the continuity and x and y-momentum equations. As the major driving force considered in the flow-field is gravitational
force, (using the gravity specifying tool of the commercial CFD software) thus gravity has been considered acting in the
negative y–axis direction.
2
3. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
III. GRID INDEPENDENCE STUDY
The triangular mesh with uniform grid spacing of 0.8 and 81600 cells have been chosen for the numerical
simulation. In order to study the effect of mesh size, grid independence study has been performed. Two different grids have
been generated with 64% (for coarser mesh) and 130% (for finer mesh) of the original grid size.
Fig. 2: Recirculation Length at Corner of the Passage.
The grid with 52224 cells has been chosen for the coarse grid study of the problem, to get an initial idea about the
numerical solution by using relatively small computational time. Due to the higher number of cells, time required to get the
converged solution with the mesh with 106129 numbers of cells is much more than that required for the numbers of cells
81600. one of the recirculation zone (before entry to the contraction zone) has been plotted against their respective grid size
as shown in Fig. 2. The non-dimensional lengths of flow separation, yr/d, are 0.112137 (at Re=223) for the coarser mesh
with 52224 numbers of cells, 0.112368 for the chosen mesh with 81600 numbers of cells and 0.112438 for finer mesh with
106129 numbers of cells on the both wall. The result shows a good agreement for the three grids and very little variation has
been observed as the grid size has been increased by almost 200%. The mesh with 81600 numbers of cells has been chosen
for further flow simulations. So the actual simulations are quite efficient, quantitative and consume less time to produce th e
numerical results.
IV. MODEL VALIDATION
The results of numerical simulations for the flow situation for the sudden contraction geometry, considering the
present flow models, have been validated with the experimental results as reported by Ozalp and Pinarbasi, [6]. The time-
averaged velocity vector plots on the x-y plane are presented for four different Re at the upstream of the contraction point are
presented in Fig. 3, to observe the effect of the presence of the contraction zone on the flow field. Fig. 3(a-c) represents the
time averaged velocity vector plots as reported by Ozalp [6] and Fig. 3(d-f) represents the time averaged velocity vector
plots obtained with the present numerical simulations considering the same flow parameters. From the velocity vector plots
(Fig. 3d-3f), it is observed that velocity vectors are parallel at the inlet of the channel and the flow is symmetric with respect
to the vertical axis of the channel geometry.
(a) (d)
3
4. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
(b) (e)
(c) (f)
Fig. 3 : Time-averaged Velocity Vector Plots, (a-c) Experimental Results [6] and (d-f) Present Numerical Results.
Near the contraction zone entrance, the flow velocity increases, as the flow area decreases and this is indicated by
the dense vector distribution. Also the radial component of velocity increases in magnitude near the contraction zone. With
the increase in Re, the flow velocity increases. The low vector density near the bottom corners of the figure indicates the
formation of flow separation zone and the separated flow revolves at the corner. Though uniform velocity of flow was
specified at the inlet, from the vector plot it can be concluded that near the contraction zone, the flow velocity is maximum at
the center of the geometry, which suggests that the flow has developed from an initial parallel form to a parabolic form.
From the above study, it is thus observed that the nature of the velocity vector plots and flow characteristics as presented in
Fig. 3(d-f) as obtained with the present simulations, matches with the experimental results of Ozalp and Pinarbasi, [6] as
presented in Fig. 3(a-c).
Fig. 4(a): Stream-wise Velocity Plot at Different Axial Location Upstream of Contraction for Re=223 [6].
Fig. 4(b): Stream-wise Velocity Plot at Different Axial Location Upstream of Contraction for Re=223, [Present Study].
The axial and radial velocity profiles at different upstream locations (y/d) near the line of contraction have been
presented in Fig. 4 and 5 or both the experimental work as reported by Ozalp and Pinarbasi, [6] and the present study. Fig. 4
represents the stream-wise flow velocity, u (Axial Velocity) distribution at different axial location (y/d) upstream of
Contraction zone for Re=223 as considered by Ozalp and Pinarbasi, [6]. The spatial co-ordinates have been modified to plot
the distribution, the x=0 point has been placed at the left wall, instead of the center as used in the numerical model. It is
evident from the velocity distribution that the flow is axi-symmetric as the velocity reaches zero at the axis at both ends of
the geometry. The results of the present study are very close to the experimental results for lower values of y/d. The velocity
is the maximum at the center and this value increases as the probe is moved towards the contraction zone. This is also
suggested from the velocity vector plot which indicates a higher concentration of velocity vectors near the contraction zone.
4
5. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
Though uniform velocity of flow was considered at the inlet, from the axial velocity distribution it can be concluded that the
flow has developed from an initial parallel form to a parabolic form near the contraction zone.
The cross-stream wise flow velocity, v (Radial Velocity) distribution has been presented in Fig. 5 for Re=336 at
four different upstream locations (y/d). The radial velocity is zero at the centerline and maximum at two locations at x/d=1.5
and 2.5. Similar to the distribution of the stream-wise velocity, here also the velocity increase with the proximity of the
orifice but this is evident only between x/d=1.0 and 3.0 for same Re.
Fig. 5(a) : Span-wise Velocity plot at Different axial location upstream of contraction for Re=336 [6].*Fig. 5(b) :
Span-wise Velocity plot at Different Axial Location Upstream of Contraction for Re=336, [Present Study].
Axial velocity distribution, Fig. 4(a) and Fig. 4(b) shows excellent qualitative and quantitative agreement between
the experimental results and present numerical results. Similarly, radial velocity distribution, Fig. 5(a) and Fig. 5(b) shows
good agreement between the experimental results and present numerical results. Also the location of bubble separation,
reattachment point and the flow vortex centre are same in both experimental and numerical result. Hence, these results
represent the good agreement of present numerical simulations with the experimental results as reported by Ozalp and
Pinarbasi, (Ref. [6]). Thus the above study (considering contraction flow geometry) represents the experimental validation of
the present numerical results.
V. RESULTS AND DISCUSSIONS
In the present study, the point of interest is to observe the occurrence and the nature of various dissipative eddies at
the convex and concave corners of the sudden change in flow geometry. The numerical analysis has been performed by
considering geometrical configuration with β=2, 4 and 8, for two different flow directions for the same geometry. Thus one
of the cases of flow, in the direction of gravity, will correspond to the contraction flow geometry. The other case, in which
the flow takes place in the opposite direction of gravity, is the case of the flow through expansion flow geometry. The flow
Reynolds number has been defined as Re U mean D , where Umean is the mean inlet velocity while D is the width of the
wider channel. The results of numerical simulations for the flow pattern in contraction geometry and for expansion geometry
are presented by using streamlines plot (Fig. 6) for the purpose of a qualitative comparison between the two.
(a) (b)
5
6. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
(c) (d)
(e) (f)
(g) (h)
Fig. 6(a-h): Streamlines Plot on the x-y plane for Contraction and Expansion section for β=4 with varying Re.
From the streamlines plot, it is clearly observed that nature of the fluid flow is axi-symmetric with respect to the
vertical axis of the channel, as the stream lines are parallel before (Fig. 6a) and after (Fig. 6b) sudden change in flow
geometry at lower Re. From the velocity vector plot (Fig. 3d), it is observed that the axial velocity vector tends to
concentrate more along the centerline region at the vicinity of the contraction zone. Thus the fluid flow seems to accelerate
as the flow Re increases. Therefore, the flow separation and flow reattachment phenomena occurs at the concave wall at
upstream of the contraction geometry (Fig.6a). Similarly, the flow separation and flow reattachment phenomena occurs at
the concave wall at downstream of sudden expansion geometry (Fig.6b) for Re=20 and β=4. From stream line plot for
sudden contraction geometry, it is also observed that there is negligible change in size of the flow vortex at the upstream of
the contraction geometry with increase in Re; whereas with increase in Re, size and shape of the flow vortices changes at the
downstream side in case of sudden expansion flow geometry.
For the sudden expansion flow geometry, it is observed that flow reattachment length yr/d (on both wall) increases
towards the downstream side with increase in ER for same Re. But, there is no significant change in yr/d incase of sudden
contraction flow geometry. For Re≥200, β=4, flow asymmetry is clearly observed; as the size and length of the flow vortices
(on both wall) are not same with respect to the vertical axis of the channel as shown in Fig. 6(h). This phenomena suggests
that the flow has already entered the unstable regime, and also that the instability is more in the flow with higher expansion
ratio (ER). For unstable flow field, the flow reattachment length yr1/d at left wall differs with respect to the flow reattachment
length yr2/d at right wall and flow structure takes wavy shape. It is observed that at ER=4 and Re=300, the length of the flow
reattachment point yr1/d at left wall increases and at right wall yr2/d decreases as shown in Fig. 6(h). Also there is a formation
6
7. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
of weaker secondary vortex (rotating in clockwise direction) at the right wall. The size of this secondary vortex increases
with increase in ER for same Re. However, for sudden contraction flow geometry there is no flow asymmetry phenomena at
the upstream of the flow passage.
Effect of length of the sudden change in flow geometry on the flow field also studied. It is observed that there is no
influence of the channel length on the formation of annular separation bubble. Flow reattachment point, secondary or tertiary
flow vortices. It indicates that the flow structure is independent of the length of the flow geometry for the present study.
Figure 7(a) represents plot for flow bifurcation point and flow reattachment length yr/d (axial) at the down stream
of the expansion zone and at the upstream of the contraction zone with the variation of Re for different ER and CR. The flow
fields corresponding to the contraction geometry as well as the expansion geometry with ER=2.00 present an axi-symmetric
formation of the separation regions on both walls. Thus only the length of one separation zone has been plotted. This plot
also represents the good agreement between the present numerical study (considering sudden expansion flow geometry) and
the numerical results as reported by Battaglia [18]. From the Fig. 7(a), it is observed that the flow reattachment length (both
yr1/d and yr2/d) increases linearly with increase in Re for fixed ER. After a certain point yr1/d increases and xr2/d decreases
sharply with increase in Re for a particular ER. This point is called Point of Bifurcation and corresponding Reynolds number
is called Critical Reynolds number Recr. As the flow structure becomes unstable after Recr, flow symmetry about the vertical
axis of the channel diminishes and the location of the center of the flow vortices (both at left wall and right wall) and also
size of the vortices changes with change in Re beyond Recr. These phenomena changes for different ER. However, for
sudden contraction flow geometry there is no existence of Recr, as the length yr/d at the upstream of the contraction zone
remains same for all CR and there is no significant change yr/d with varying Re. For the flow in the downward direction
(contraction flow geometry) separations form at the upstream corners but it is much smaller in size as compared to the
reversed flow (expansion flow geometry), where the major separation occurs at the downstream. This can be attributed to the
effect of gravity, increasing the separation for the upward flow.
Variation of radial length of flow separation zone both for sudden expansion and sudden contraction flow
geometry, are presented in Fig. 7(b). From the plot it is observed that, a similar type of distribution was previously shown by
Durst et al. [4]. This suggests the existence of a critical Reynolds number for the flow through sudden contraction. It can be
seen that above this point the size of the recirculation zone increases almost linearly.
(a) (b)
Fig. 7: (a) Variation of axial Length (b) Variation of Radial length of flow Separation zone for Expansion and
Contraction flow Geometry.
However, for the case of the upward flow, which forms separation in the downstream corners of the channel, the
critical point in the flow is the point where the flow at the downstream starts to become asymmetric. Although, it is seen that
for the case of β=2, there is no asymmetry, for the cases of β=4 and 8, this instability is clearly visible above a particular
value of Re. It can, therefore, be safely assumed that for the case of β=2 the critical Reynolds number exists but it is outside
the range of the current study. The curve for β=2 shows very good linear variation of recirculation length and width with
Reynolds number.
Figure 8(a) and (b) represents the variations of axial velocity and pressure along the centerline of the flow both for
the sudden expansion and contraction flow geometry with three different size ratios (β) and at Re=223. From Figure 8(a), it
is observed that, the dimensionless axial velocity (u/Umean) increases with decrease in yr/d and reaches maximum value at the
point of sudden contraction point (yr/d=0) for same CR. With the increases in CR, the peak value of u/Umean also increases.
Where as for sudden expansion flow geometry, u/Umean decreases slightly after the point of sudden expansion with increase
in yr/d and there is smaller variation in u/Umean with the increase in ER in comparison to the increase in CR. Similarly, from
Figure 8(b), it is observed that, the dimensionless pressure (p/Pin) decreases gradually along the centerline with decrease in
yr/d and suddenly falls at the point of sudden contraction point (yr/d=0) for same CR. Similar observation is found for
varying CR. Whereas for sudden expansion flow geometry, p/Pin decreases with increase in yr/d and reaches minimum value
7
8. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
at the point of sudden expansion and again p/Pin increases with increase in yr/d and there is smaller variation in p/Pin with the
increase in ER in comparison to the increase in CR. It is seen that the presence of the abrupt contraction is much more in the
sudden variations of velocity and pressure, for the same inlet conditions, than that of a sudden expansion. There is an
appreciable jump (rise) in axial velocity and drop in pressure for the former case. Whereas for the case of a sudden
expansion, the variation is much more gradual and compared to the sudden contraction case, these variations are negligible.
So it is observed that for the same channel size ratio, contraction affects the basic flow parameters drastically than the
presence of a sudden expansion in the flow passage.
(a) (b)
Fig 8 (a) Variation of Axial Velocity along the Centerline for Re=223; (b) Variation of Pressure along the Centerline
for Re=223.
From the Fig. 7(a), it is clear that the bifurcation point (for sudden expansion flow geometry), that is the upper
point of stability, shifts towards lower values of Reynolds number for flow geometries with higher expansion ratio (ER).
This signifies the relative instability of these flow fields. The values of Recr for different ER are presented in Table 1. So
from these analysis, it could be concluded that, for a fixed fluid flow rate, the flow tends to become unstable with the
increase in expansion ratio or in other words the flow for higher expansion ratio becomes unstable at low flow rates and
vice-versa for sudden expansion flow geometry. Whereas there is no such phenomena for sudden contraction flow geometry.
Table: 1
Expansion Ratio (ER) Critical Reynolds Number (Recr)
2 -
4 200
8 200
VI. CONCLUSIONS
In the present work, the analysis of several two-dimensional flow fields through sudden contraction and sudden
expansion geometries under the action of gravity has been carried out numerically to get a better understanding of the sudden
contraction and sudden expansion flow characteristics as well as to compare these two similar but opposing flow situations.
The study has provided detailed numerical results for varying contraction ratio and expansion ratio (β) with varying Re.
Physical characteristics of the flow of fluid for the case of the contraction flow, chosen from the study of Ozalp and
Pinarbasi, [6], for the purpose of the experimental validation of present numerical results.
A good qualitative and quantitative agreement has been observed between the present numerical results
(considering contraction flow geometry) and experimental results as reported by Durst F. and Loy T. [4]. From the
streamlines plots, the presence of upstream and/or downstream separation zones is clearly observed for different size ratio
(β) with varying Re. The sudden contraction, as compared to the sudden expansion, is seen to have drastic impact on the flow
field for the same β. Gain of axial velocity (u/Umean) along the centerline is maximum at the point of contraction with respect
to the sudden expansion pint and the effect is more with hire CR ratio in comparison to the higher ER. For the flow in the
downward direction (contraction flow geometry) separations form at the upstream corners but it is much smaller in size as
compared to the reversed flow (expansion flow geometry), where the major separation occurs at the downstream. This can be
attributed to the effect of gravity, increasing the separation for the upward flow. Due to the high viscosity of the fluid, at low
Reynolds Number the two-dimensionality of the actual flow has been considered.
Nomenclature
β Width Ratio = D/d
Viscosity of Flowing Fluid, (N-sec/m2)
Density of Flowing Fluid, (kg/m3)
D Width of the Inlet Flow Passage, (m)
8
9. Investigation of Newtonian Fluid Flow through a Two-dimensional Sudden Expansion…
d Width of the Outlet Flow Passage, (m)
lu Length of the Passage Upstream of the Contraction, (m)
ld Length of the Passage Downstream of the Contraction, (m)
Re Reynolds Number (Re= Umean d /)
Umean , Um The average Inlet Velocity, (m/sec)
x, y Cartesian Coordinate System, (2D).
u Axial Velocity, (m/sec)
v Radial Velocity, (m/sec)
Yr/D Non-dimensional Recirculation Zone Height
Xr/D Non-dimensional Recirculation Zone Width
REFERENCE
[1]. Astarita G., Greco G., 1966, “Excess Pressure Drop in Laminar flow through sudden Contraction”, I & EC Fundamentals, Vol.7,
No. 1, pp. 27-31.
[2]. Christiansen E. B., Kelsey S. J., Carter T. R., 1972, “Laminar Tube Flow through Sudden Contraction”, AlChE Journal, Vol. 18,
No. 2, pp. 372-380.
[3]. Vrentas J.S., Duda J.L., 1973, “Flow of a Newtonian fluid through a Sudden Contraction”, Ind. Eng. Chem. Fundam., Vol. 11,
No. 4, pp. 590-593.
[4]. Durst F., Loy T., 1985, “Investigations of Laminar flow in a pipe with Sudden Contraction of cross-sectional area”, Computers &
Fluids Vol. 13, No. l, pp. 15-36.
[5]. Mitsoulis E., Vlachopoulos J., 1985, “Effect of Reynolds number in Laminar flow through a Sudden Planar Contraction”, AlChE
Journal, Vol. 31, No. 10, pp. 1736-1739.
[6]. Ozalp C., Pinarbasi A., Fakilar M.S., Sahin B., 2007, “PIV measurements of flow through a Sudden Contraction”, Flow
Measurement and Instrumentation, Vol. 18, pp. 121–128.
[7]. Chiang T.P., Sau A., Hwang R.R. “Asymmetry and Bifurcations in three-dimensional Sudden-Contraction channel flows”
Physical Review E 83, 046313, pp. 1-14.
[8]. Binding D.M., 1988, “An Approximate analysis for Contraction and Converging flows” Journal of Non-Newtonian Fluid
Mechanics, 27, pp. 173-189.
[9]. Binding D.M., 1991, “Further Considerations of Axisymmetric Contraction flows”, Journal of Non-Newtonian Fluid Mechanics,
41, pp. 27-42.
[10]. Alves M A., Oliveira P. J., Pinho F. T., 2004 “On the effect of contraction ratio in viscoelastic flow” J. Non-Newtonian Fluid
Mech. 122, pp.117–130.
[11]. Schimdt J. , Friedel L., 1997, “Two Phase Pressure Drop in Sudden Contractions in duct areas” Int. J. Multiphase Flow Vol. 23,
No. 2, pp. 283-299.
[12]. Pal R., Hwang C., 1997, “Flow of 2-phase Oil/Water through sudden expansion and contraction”, Chemical Engineering Journal,
68, pp. 157-163.
[13]. Kourakos V.G., Rambaud P., Chabane S., Pierrat D., Buchlin J. M., “Two-phase flow modeling within Expansion and
Contraction Singularities”
[14]. Chen I. Y., Tseng C.-Y., Lin Y.-T., Wang C.-C., 2009, “Two-phase Flow Pressure change subject to Sudden Contraction”, Int. J.
of Multiphase Flow, 35, pp. 297–306.
[15]. Patankar S.V., 1980, “Numerical Heat Transfer”, North Holland.
[16]. Macagno, E. O., Hung, T. K., 1967, “Computational and Experimental Study of a Captive Annular Eddy”, J. Fluid Mech., vol.
28, part 1, pp. 43-64.
[17]. Badekas, D., Knight, D.D., 1992, “Eddy Correlations for Laminar Axisymmetric Sudden Expansion Flows”, Journal of Fluids
Engineering, Vol. 114, pp. 119-121.
[18]. Battaglia, F., Tavener, S.J., Kulkarni, A.K., Merkle, C.L., 1997, “Bifurcation of Low Reynolds Number Flows in Symmetric
Channels”, AIAA Journal, vol. 35, no. 1, pp. 99-105.
[19]. Ray S., Biswas N. and Roy P. C., 2012, “A Numerical Investigation of Flow through a Sudden Expansion: Effect of Expansion
Ratio”, Global J. of Mech., Engg. & Comp. Sciences, vol. 2 (1), pp.31-37.
9