Inertial resistance term in Fluent
 

Hi. I am new to Porous media modeling and I am studying some basics which i will implement with Ansys Fluent. My question is very basic but please i couldn't find answer in this forum.
According to Fluent help, inertial resistance term for homogeneous porous media is C/2*rou*|v|v (where C is the inertial resistance coefficient and 'rou' is density). How is this term derived? Its not the original Forchheimer's term which I read in book of Neild and Bejan and many papers related to flow in tube filled with porous media as C/sqrt(K)*rou*|v|v (K is permeability of porous medium). I wonder if it is a general inertial resistance term applicable for wide range of porous geometries.
I believe there will be much difference between Fluent's inertial resistance and Forchheimer equation's resistance term because K is usually very low which will effect results.
Please help.

inertial resistance term for homogeneous porous media is C/2*rou*|v|v
by comparing the terms of the ansys equation with the momentum eqaution you will found in the momentum equation for the porous medium the C/2 is equivalent to 2*C_f/SQR(K)
where C_f is the coefficient of friction for the porous medium and it is dimensionless
and SQR(K) is the square root of the perimability and its dimension is 1/m
by comparing the dimensions they are the same.