A two-energy equation model for conduction and convection in porous media

2001 ◽  
Vol 44 (22) ◽  
pp. 4375-4379 ◽  
Author(s):  
Akira Nakayama ◽  
Fujio Kuwahara ◽  
Masazumi Sugiyama ◽  
Guoliang Xu
Keyword(s):  
Porous Media ◽  
Energy Equation ◽  
Equation Model ◽  
Convection In Porous Media

Using Direct Numerical Simulations for Investigating Physics of Turbulence in Porous Media

2017 ◽  
Author(s):  
Y. Jin ◽  
A. V. Kuznetsov
Keyword(s):  
Porous Media ◽  
Turbulence Models ◽  
Maximum Size ◽  
Reynolds Numbers ◽  
Direct Numerical Simulations ◽  
Velocity Measurements ◽  
Turbulent Eddies ◽  
Size Limitation ◽  
Large Eddies ◽  
Convection In Porous Media

One of the most controversial topics in the field of convection in porous media is the issue of macroscopic turbulence. It remains unclear whether it can occur in porous media. It is difficult to carry out velocity measurements within porous media, as they are typically optically opaque. At the same time, it is now possible to conduct a definitive direct numerical simulation (DNS) study of this phenomenon. We examine the processes that take place in porous media at large Reynolds numbers, attempting to accurately describe them and analyze whether they can be labeled as true turbulence. In contrast to existing work on turbulence in porous media, which relies on certain turbulence models, DNS allows one to understand the phenomenon in all its complexity by directly resolving all the scales of motion. Our results suggest that the size of the pores determines the maximum size of the turbulent eddies. If the size of turbulent eddies cannot exceed the size of the pores, then turbulent phenomena in porous media differ from turbulence in clear fluids. Indeed, this size limitation must have an impact on the energy cascade, for in clear fluids the turbulent kinetic energy is predominantly contained within large eddies.

Passive Heat Transfer in Porous Enclosures Using a Two-Energy Equation Model

2012 ◽  
Author(s):  
Marcelo J. S. deLemos ◽  
Paulo H. S. Carvalho
Keyword(s):  
Heat Transfer ◽  
Energy Equation ◽  
Equation Model ◽  
Thermal Conductivity Ratio ◽  
Governing Equations ◽  
Flow And Heat Transfer ◽  
Energy Models ◽  
Different Temperatures ◽  
Volume Method ◽  
Generalized Coordinate

This paper presents computations for natural convection within a porous cavity filled with a fluid saturated permeable medium. The finite volume method in a generalized coordinate system is applied. The walls are maintained at constant but different temperatures, while the horizontal walls are kept insulated. Governing equations are written in terms of primitive variables and are recast into a general form. Flow and heat transfer characteristics are investigated for two energy models and distinct solid-to-fluid thermal conductivity ratio.

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