I need your suggestion / which model?
 

Hi

I'm trying to simulate the flow of water+sands (sizing from 1 micron to 10 mm) in a large tank for 2 hours of physical time. (gravity is important)

Due to presence of some chemicals, these sans may coalesce and form larger sands. In addition, due to shear stresses, large sands may breakup to smaller pieces.

Which multiphase flow models/approaches would you use to solve this problem?

any suggestions?