Simulation of Turbulent Flow Through Hybrid Porous Medium: Clear Fluid Domains

2000 ◽  
Author(s):  
Marcelo J. S. de Lemos ◽  
Marcos H. J. Pedras
Keyword(s):  
Porous Medium ◽  
Turbulent Flow ◽  
Control Volume ◽  
Numerical Technique ◽  
Governing Equations ◽  
Clear Fluid ◽  
First Case ◽  
Flow Through ◽  
Control Volume Approach ◽  
Porous Obstacle

Abstract Turbulent flow in a channel, totally and partially filled with a porous medium, is simulated with a proposed turbulence model. Two cases are analyzed, namely clear flow past a porous obstacle and flow through a porous medium having a cavity with a higher porosity. Mean and turbulence quantities were solved within both computational domains using a single numerical technique. The control volume approach was used to discretize the governing equations. In the first case analyzed, the flow penetration into the porous substrate is accompanied by generation of turbulence kinetic energy within the obstacle. In the second geometry, the flow is pushed towards the cavity as porosity increases.

Experimental Study of Turbulent Flow in Two-Dimensional Porous Media

2009 ◽  
Author(s):  
Sintia Bejatovic ◽  
Martin Agelinchaab ◽  
Mark F. Tachie
Keyword(s):  
Porous Medium ◽  
Porous Media ◽  
Turbulent Flow ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Channel Height ◽  
Two Dimensional ◽  
Clear Fluid ◽  
Test Channel ◽  
Flow Through

The paper reports on an experimental investigation of turbulent flow through model two-dimensional porous media. The porous media was bounded on one side by a solid plane wall and on the other side by a zone of clear fluid. The model porous media comprised of square arrays of circular acrylic rods that were inserted into precision holes drilled onto pairs of removable plates. The removable plates were then inserted into groves made in the side walls of the test channel. The rods fill about 59% of the channel height. Different combinations of rod diameter and center-to-center spacing were used to produce solid volume fractions that ranged from 0.11 to 0.44. The Reynolds number based on the bulk velocity of the approach flow and channel height was 16800. A high resolution particle image velocimetry (PIV) system was used to conduct detailed velocity measurements within the porous media and the adjacent clear fluid. The results demonstrate that permeability of the porous medium is more useful in correlating the flow characteristics than the porosity or solid volume fraction. Irrespective of rod diameter or spacing, a decrease in permeability of the porous medium produced a lower value of the dimensionless slip velocity. A decrease in permeability also produced higher resistance to the fluid flow through the porous medium. As a result, a larger fraction of the approach flow is channeled through the clear zone adjacent to a porous medium with lower permeability than those with relatively higher permeability. It was also observed that spatially averaged profiles of the mean velocities and turbulent quantities depend strongly on permeability.

scholarly journals Conducting dusty fluid flow through a constriction in a porous medium

2016 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Madhura K R ◽  
Uma M S
Keyword(s):  
Porous Medium ◽  
Hartmann Number ◽  
Equations Of Motion ◽  
Fluid Phase ◽  
Dust Particles ◽  
Governing Equations ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
Flow Through ◽  
Constricted Channel

<p><span lang="EN-IN">The flow of an unsteady incompressible electrically conducting fluid with uniform distribution of dust particles in a constricted channel has been studied. The medium is assumed to be porous in nature. The governing equations of motion are treated analytically and the expressions are obtained by using variable separable and Laplace transform techniques. The influence of the dust particles on the velocity distributions of the fluid are investigated for various cases and the results are illustrated by varying parameters like Hartmann number, deposition thickness on the walls of the cylinder and the permeability of the porous medium on the velocity of dust and fluid phase.</span></p>

scholarly journals Chemical Entropy Generation and MHD Effects on the Unsteady Heat and Fluid Flow through a Porous Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Gamal M. Abdel-Rahman Rashed
Keyword(s):  
Magnetic Field ◽  
Porous Medium ◽  
Fluid Flow ◽  
Entropy Generation ◽  
Lewis Number ◽  
Heat Transfer Fluid ◽  
Governing Equations ◽  
Flow Through ◽  
Heat And Fluid Flow ◽  
Chemical Reaction Parameter

Chemical entropy generation and magnetohydrodynamic effects on the unsteady heat and fluid flow through a porous medium have been numerically investigated. The entropy generation due to the use of a magnetic field and porous medium effects on heat transfer, fluid friction, and mass transfer have been analyzed numerically. Using a similarity transformation, the governing equations of continuity, momentum, and energy and concentration equations, of nonlinear system, were reduced to a set of ordinary differential equations and solved numerically. The effects of unsteadiness parameter, magnetic field parameter, porosity parameter, heat generation/absorption parameter, Lewis number, chemical reaction parameter, and Brinkman number parameter on the velocity, the temperature, the concentration, and the entropy generation rates profiles were investigated and the results were presented graphically.

One-Dimensional Fully Developed Turbulent Flow through Coarse Porous Medium

2014 ◽  
Vol 19 (7) ◽  
pp. 1491-1496 ◽  
Author(s):  
Mohammad Sedghi-Asl ◽  
Hassan Rahimi ◽  
Javad Farhoudi ◽  
Abdolhossein Hoorfar ◽  
Sven Hartmann
Keyword(s):  
Porous Medium ◽  
Turbulent Flow ◽  
One Dimensional ◽  
Fully Developed Turbulent Flow ◽  
Flow Through

Numerical Simulation of Laminar Confined Impinging Jet in a Composite Channel

2008 ◽  
Author(s):  
Marcelo J. S. de Lemos
Keyword(s):  
Porous Layer ◽  
Control Volume ◽  
Numerical Technique ◽  
Simple Algorithm ◽  
Local Distribution ◽  
Governing Equations ◽  
Stagnation Region ◽  
Volume Method ◽  
Material Porosity ◽  
Macroscopic Equations

This work shows numerical results for a jet impinging onto a flat plane covered with a layer of a porous material. Porosity of the porous layer is varied in order to analyze its effect on the local distribution of Nu. Macroscopic equations for mass and momentum ae obtained based on the volume-average concept. The numerical technique employed for discretizing the governing equations was the control volume method with a boundary-fitted non-orthogonal coordinate system. The SIMPLE algorithm was used to handle the pressure-velocity coupling. Results indicate that inclusion of a porous layer decreases the peak in Nu avoiding excessive heating or cooling near the stagnation region.

Mass Dispersion Coefficients for Turbulent Flow in an Infinite Porous Medium

Volume 1 ◽  
2004 ◽  
Author(s):  
Maximilian S. Mesquita ◽  
Marcelo J. S. de Lemos
Keyword(s):  
Porous Medium ◽  
Control Volume ◽  
Fluid Phase ◽  
Pore Scale ◽  
Simple Method ◽  
Flow Equations ◽  
Mass Dispersion ◽  
Spatially Periodic ◽  
Linear Effects ◽  
Control Volume Approach

In this work, mass dispersion tensors were calculated within an infinite porous medium formed by a spatially periodic array of longitudinally-displaced cylindrical rods. For the sake of simplicity, just one unit-cell, together with periodic boundary conditions for mass and momentum equations, and Neumann conditions for the mass concentration, was used to represent such medium. The numerical methodology herein employed is based on the control volume approach. Turbulence is assumed to exist within the fluid phase. High and low Reynolds k-e models were used to model such non-linear effects. The flow equations at the pore-scale were numerically solved using the SIMPLE method applied to a non-orthogonal boundary-fitted coordinate system. Integrated mass fraction results were compared with existing data in the literature.

scholarly journals Simulation of the Flow Through Porous Layers Composed of Converging-Diverging Capillary Fissures or Tubes

2018 ◽  
Vol 23 (1) ◽  
pp. 161-185 ◽  
Author(s):  
A. Walicka
Keyword(s):  
Porous Medium ◽  
Power Law ◽  
Analytical Method ◽  
Algebraic Equations ◽  
Governing Equations ◽  
Flow Rates ◽  
Pressure Drops ◽  
Porous Layers ◽  
Linear Algebraic Equations ◽  
Flow Through

AbstractIn this paper, a porous medium is modelled by a network of converging-diverging capillaries which may be considered as fissures or tubes. This model makes it necessary to consider flows through capillary fissures or tubes. Therefore an analytical method for deriving the relationships between pressure drops, volumetric flow rates and velocities for the following fluids: Newtonian, polar, power-law, pseudoplastic (DeHaven and Sisko types) and Shulmanian, was developed. Next, considerations on the models of pore network for Newtonian and non-Newtonian fluids were presented. The models, similar to the schemes of central finite differences may provide a good basis for transforming the governing equations of a flow through the porous medium into a set of linear or quasi-linear algebraic equations. It was shown that the some coefficients in these algebraic equations depend on the kind of the capillary convergence.

Heat Transfer in a Suddenly Expanded Turbulent Flow Past a Porous Insert Using Linear and Non-Linear Eddy-Viscosity Models

2002 ◽  
Author(s):  
Marcelo J. S. de Lemos ◽  
Marcelo Assato
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Eddy Viscosity ◽  
Control Volume ◽  
Numerical Technique ◽  
Turbulence Models ◽  
Wall Functions ◽  
Porous Insert ◽  
Flow Past ◽  
Non Linear

This work presents numerical results for heat transfer in turbulent flow past a backward-facing-step channel with a porous insert using linear and non-linear eddy viscosity macroscopic models. The non-linear turbulence models are known to perform better than classical eddy-diffusivity models due to their ability to simulate important characteristics of the flow. Parameters such as porosity, permeability and thickness of the porous insert are varied in order to analyze their effects on the flow pattern, particularly on the damping of the recirculating bubble after the porous insertion. The numerical technique employed for discretizing the governing equations is the control-volume method. The SIMPLE algorithm is used to correct the pressure field. Wall functions for velocity and temperature are used in order to bypass fine computational close to the wall. Comparisons of results simulated with both linear and non-linear turbulence models are presented.

Gas-assisted laser repetitive pulsed heating of a steel surface

1998 ◽  
Vol 212 (8) ◽  
pp. 741-757 ◽  
Author(s):  
S Z Shuja ◽  
B S Yilbas
Keyword(s):  
Steel Surface ◽  
Control Volume ◽  
Solid Substrate ◽  
Gas Jet ◽  
Governing Equations ◽  
Pulsed Heating ◽  
Thermal Integration ◽  
Pulsed Laser Heating ◽  
Jet Velocities ◽  
Control Volume Approach

The present study is carried out to investigate the effect of the assist gas jet on the thermal integration due to repetitive pulsed laser heating. Air is considered as the assist gas, which impinges coaxially with the laser beam and orthogonal to a steel surface. The low Reynolds number k-ε model is introduced, based on previous studies, to account for the turbulence. A numerical scheme using the control volume approach is employed to solve the two-dimensional axisymmetric governing equations of flow and heat conduction. The transport properties of the assist gas and of the solid substrate are considered as variable. The study is extended to include two gas jet velocities and three laser pulse types. It is found that thermal integration in the solid substrate is possible for a low-intensity power ratio of the repetitive pulses and the influence of the assist gas jet on the temperature profiles is almost insignificant.

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