Eularian granular two phase model

Kelly

Hi,

I am using Eularian granular two phase model (water and sand as two phases). I'm trying to model water flow over the sand. The water&sand interface is predicted similarly to the lab data by FLUENT. However, I would also expect some portion of the sand will be stirred up to the upper water phase close to the free surface. As I plot out phase-2 volume fraction, there is almost nothing above the interface (defined as vf=0.5). That is, sand vf is almost 0 above the interface. It is not correct. There should be some sand concentration in the upper water phase. Do you know the probable reason for this? Thanks.