I am modeling a laminar gas flow through porous media. The fluent manual said that the porous media may reduces to Darcy's law, and I do not have to define the inertial resistance factor, C_2. However, I still do not know how to define the permeability, alph.

Sean:

Alpha is the inverse of the permeability. To obtain an estimation of the permeability tensor, you need to know the porosity of the porous media. Also, the unit vector direction is important.

Mel

Mel: You are so kind to give me an answer. Do you mean that I can deduce the viscous resistance coefficient, which is the inverse of the permeability, from the porosity of the porous media in a vector direction? Fluent manual told me that porosity is the volume fraction of fluid within the porous region.

sean

Sean:

The permeability is a tensor, you need a magnitude and two direction to specify the permeability. The permeability is a function of the porosity, i.e. pore volume fraction.

Mel

[vittal]

Can any one help me out how to calculate permeability and C2 if i know porosity.I am unable to know how the unit directions are mentioned.
Please help me in this process.