[segersson]

Hi,
I'm trying to model air flow through vegetation and need to add a negative source term to the momentum equation in simpleFoam. I would appreciate some advice to get this right (I'm quite new to OpenFOAM...).

For the different directions the source term is:
Sx = -0.5*rho*Cd*abs(u)*u
Sy = -0.5*rho*Cd*abs(v)*v
Sz = ...
,where Cd is a constant.

My questions are:
1. After I have created a volScalarField for Cd, how can I express the term in OpenFOAM in a nice way?
( S = -0.5*rho*Cd*U&U gives me the wrong sign I guess...)

3. Is it correct to insert the source term in simpleFoam.C as:

solve(UEqn() == S -fvc::grad(p));

Do I have to include the source term anywhere else in the SIMPLE algorithm?

3. If I want the term to be explicit, are there any advantage in using the SuSp(..,..) function?

Regards
David