Turbulent flow in porous medium
 

Hi,

I am solving a turbulent conjugate heat transfer problem in which water enters the domain at 11000 Re into a duct. After flowing some distance in the duct, it enters a porous medium and flows through it. Re inside the porous medium, based on true velocity and pore size is 600. I am using k-omega model to solve for turbulence. CFX uses the same model inside the porous medium also. I have questions regarding the same.

1. How are the momentum equations for porous medium modified for turbulent flow? CFX theory manual says that an effective viscosity is used in the momentum equation. Is this effective viscosity in the sum of laminar and eddy viscosity, as in normal Reynolds averaged momentum equation for fluid flow?

2. In case of the energy equation, the manual says that an effective thermal diffusivity is used. Is this effective thermal diffusivity the sum of effective thermal diffusivity for porous medium and the ratio meu_t/Pr_t (i.e. ratio of eddy viscosity and turbulent Prandtl number, similar to the Reynolds averaged energy equation for fluid flow)


3. what is 'H' in Eq. 1-259? Is it total enthalpy i.e. h+0.5*U*U?


I am attaching the relevant excerpts from CFX manual for reference.

Thanks for your inputs,
Chander

Excerpts from cfx manual

Hi Dear..
I am am starting my thesis which is similar to your problem. i want to know momentum and energy equation which fluent or CFX uses for turbulent flow in the porous region. would u please help me with this. i mean any references or..?

It is all described in the CFX and Fluent documentation. Have you looked in there?

i have checked CFX and fluent but i couldn't find energy equation for porous media in turbulent regime