Hi,

I am using cfx5.6 and I am quite unexperienced in cfd.

I tried to apply a general momentum source to simulate an anisotropic flow resistance in a single-phase flow. The geometry is cubical. The flow goes straight through the cube (z-Direction), the walls have fee-slip. For the source I used the nonlinear expression (At first only one direction for testing purpose):

GMSz=-const*abs(w)^0.8*w

Everything worked fine and the solution converged. My problem is, that the velocity is decreasing on the way through the cube without increase of the density. That means to me, that the momentum source (more a sink)is decreasing the mass during its way. I thought it would only decrease the momentum and lead to a higher pressure drop. Where is the mistake I make?

Thanks very much in advance

Johannes

Dear Joahannes, I do not think you are making a mistake, as you can see I have a post further down, where I also have problems. In my case does the velocity though increase, and I have still not solved the problem. I think it is a free of charge extra facility in CFX5.6 . (I am happy you also have problems I was wondering if I was the only user that had this problem "or the only that have discovered it"). Not much help for you though Jens

Thanks for the response, Jens.