Effects of Buoyancy Forces on Immiscible Water/Oil Displacements in a Vertically Oriented Porous Medium

1995 ◽  
Vol 50 (4) ◽  
pp. 517-536 ◽  
Author(s):  
S. R. Thirunavu ◽  
G. H. Neale
Keyword(s):  
Porous Medium ◽  
Buoyancy Forces

Mixed Convective Heat Transfer From a Heated Horizontal Plate in a Porous Medium Near an Impermeable Surface

1988 ◽  
Vol 110 (2) ◽  
pp. 390-394 ◽  
Author(s):  
P. H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Saturated Porous Medium ◽  
Forced Flow ◽  
Horizontal Plate ◽  
Flowing Fluid ◽  
Buoyancy Forces ◽  
Two Dimensional Flow

Two-dimensional flow over a horizontal plate in a saturated porous medium mounted near an impervious adiabatic horizontal surface and subjected to a horizontal forced flow has been numerically investigated. The plate is heated to a uniform temperature that is higher than the temperature of the flowing fluid. The conditions considered are such that the buoyancy forces have an effect on the flow and, therefore, on the heat transfer rate from the plate. The full governing equations, written in dimensionless form, have been solved for a range of values of the governing parameters using the finite element method. The heat transfer rate from the plate is influenced both by the dimensionless depth of the plate below the surface and the importance of the buoyancy forces, the latter having been characterized by a parameter which is equal to the ratio of the Darcy–Rayleigh number to Peclet number. The conditions under which these parameters have a negligible effect on the heat transfer rate are discussed.

scholarly journals INVASION PERCOLATION WITH A HARDENING INTERFACE UNDER GRAVITY

2010 ◽  
Vol 21 (07) ◽  
pp. 903-914 ◽  
Author(s):  
C. L. N. OLIVEIRA ◽  
F. K. WITTEL ◽  
J. S. ANDRADE ◽  
H. J. HERRMANN
Keyword(s):  
Porous Medium ◽  
Capillary Forces ◽  
Bond Number ◽  
Invasion Percolation ◽  
Hardening Behavior ◽  
Hardening Effect ◽  
Buoyancy Forces ◽  
Capillary Pressures ◽  
A Site ◽  
Invasion Patterns

We propose a modified Invasion Percolation (IP) model to simulate the infiltration of glue into a porous medium under gravity in 2D. Initially, the medium is saturated with air and then invaded by a fluid that has a hardening effect taking place from the interface towards the interior by contact with the air. To take into account that interfacial hardening, we use an IP model where capillary pressures of the growth sites are increased with time. In our model, if a site stays for a certain time at interface, it becomes a hard site and cannot be invaded anymore. That represents the glue interface becoming hard due to exposition with the air. Buoyancy forces are included in this system through the Bond number which represents the competition between the hydrostatic and capillary forces. We then compare our results with results from literature of non-hardening fluids in each regime of Bond number. We see that the invasion patterns change strongly with hardening while the non-hardening behavior remains basically not affected.

Unsteady MHD Chemically Reacting and Radiating Mixed Convection Slip Flow Past a Stretching Surface in a Porous Medium

2017 ◽  
Vol 377 ◽  
pp. 200-210 ◽  
Author(s):  
Adetayo Samuel Eegunjobi ◽  
Oluwole Daniel Makinde ◽  
Srinivas Jangili
Keyword(s):  
Porous Medium ◽  
Mixed Convection ◽  
Fluid Velocity ◽  
Mass Transfer Rate ◽  
Convection Flow ◽  
Radiation Chemical ◽  
Local Skin ◽  
Unsteady Mixed Convection ◽  
Medium Permeability ◽  
Buoyancy Forces

This paper studies the effects of combined buoyancy forces, thermal radiation, chemical reaction, velocity slip, magnetic field and porous medium permeability on unsteady mixed convection flow of electrically conducting fluid past a stretching sheet embedded in a porous medium. Appropriate governing equations are procured and also reduced to set of nonlinear coupled ordinary differential equations by means of suitable similarity transformations. The boundary valued problem is numerically tackled using the fourth-fifth order Runge-Kutta-Fehlberg integration approach with shooting outline. Various controlling parameters effects on the fluid velocity, temperature and kinds concentration profiles together with local skin friction, Nusselt number and Sherwood number are presented diagrammatically and deliberated upon quantitatively. It is found that buoyancy forces increment enhance both heat and mass transfer rate while thermal and concentration boundary layer denseness diminished.

scholarly journals Natural convection in a triangular cavity filled with a nanofluid-saturated porous medium using three heat equation model

2016 ◽  
Vol 94 (6) ◽  
pp. 604-615 ◽  
Author(s):  
Mahmoud Sabour ◽  
Mohammad Ghalambaz
Keyword(s):  
Mass Transfer ◽  
Porous Medium ◽  
Nusselt Number ◽  
Natural Convection ◽  
Base Fluid ◽  
Concentration Distribution ◽  
Average Nusselt Number ◽  
Equation Model ◽  
Buoyancy Forces ◽  
Buoyancy Ratio

The present study aims to examine the local thermal non-equilibrium natural convection heat and mass transfer of nanofluids in a triangular enclosure filled with a porous medium. The effect of the presence of nanoparticles and the thermal interaction between phases on the flow, temperature distribution of phases, the concentration distribution of nanoparticles as well as the Nusselt number of phases is theoretically studied. The interaction between the phases of nanoparticles and the base is taken into account by using a three thermal energy equation model while the concentration distribution of nanoparticles is modeled by Buongiorno’s model. A hot flush element is mounted at the vertical wall of the triangle enclosure to provide a constant temperature of Th while the inclined wall is at a constant temperature of Tc. A three heat equation model by considering the local thermal non-equilibrium model of nanoparticles, the porous medium, and the base fluid is developed and utilized for natural convection of nanofluids in an enclosure. The drift-flux of nanoparticles due to the nano-scale effects of thermophoresis and Brownian motion effects is addressed. The governing equations are represented in a non-dimensional form and solved by employing the finite element method. The results indicate that the increase of Rayleigh number shows a significant increase in the average Nusselt number for the base fluid phase, a less significant increase in the average Nusselt number for the solid matrix phase, and almost an insignificant effect in the average Nusselt number of the nanoparticle phase. Increasing the buoyancy ratio parameter (the ratio of mass transfer buoyancy forces to the thermal buoyancy forces) tends to reduce and increase the average Nusselt number in fluid and porous phases, respectively. An optimum value of buoyancy ratio parameter for the average Nusselt number of the nanoparticle phase is observed.

Sign in / Sign up

Export Citation Format

Share Document