I am doing the simulation on gas-solid two phase flow system using CFX4.3 now. On the residual plot, the velocity residual value of solid phase always oscillate. Does anyone know how to deal with it? I use the multi-fluid model.

I have been studied this kind of flow and I've always had difficulties to keep redisuals without oscillate.

I suggest to use one of these options:

- Transient Flow (lower time steps higher relaxation); - Courant false time steps - False time steps - Under relaxations factors

But the oscilation will always exists, unfortunely.

Good luck