[amirfard]

I am going to test the LES turbulent channel flow of OpenFOAM.

In the original test case (OpenFOAM 10) fvConstraints is used. Then I want to retest the problem by just setting the semiImplicitSource for momentum equation (i.e. a body force) in "fvModels". I set the body force according to g= u_\tau^2 * density / H. Here, H is the half channel height. And u_\tau is obtained from the Reynolds number definition for Re=395 as Re_\tau = u_\tau.H/(\nu).

Interestingly, the velocity profile that I obtain is very different from the case of using fvConstaints.

Can anybody explain why and how to set the pressure gradient (or body force) in a turbulent channel flow?