[Natalie2210]

Hi everybody,

I'm simulating flow through porous media and it works well with FLUENT. However, I have a question concerning the theory behind the flow:

Basically, two different formulations can be used, one is denominated the "superficial velocity formulation" and the other one is the "physical velocity formulation". In the superficial velocity formulation, a sink term is added the usual momentum equation,

S = mu/alpha * v (in my model I neglect the inertia resistance)

mu is the dynamic viscosity, v the velocity and alpha denotes the permeability. However, the solution changes (as it should) if I use different values for the porosity gamma. I now wonder where the porosity enters the model equations within the superficial velocity formulation? As far as I know, the permeability does not depend on the porosity, however, in the ANSYS FLUENT 12.0 Users-Guide - 7.2.3, I find the following statement:
" Both K and C2 are functions of (1-gamma). "
What kind of relation is that and how is it theoretically justified?

Thank you for any piece of advice,
Natalie