Regarding Boundary Condition at Outlet for gas-solid simulation
 

Hi all,

I have two quarries regarding Boundary Condition at Outlet for solid granular simulation please spare some time to answering them and helping me. The quarries are as follow:

1.) In fluent user guide it is clearly mentioned that outflow boundaries cannot be used in the following cases:
a.) If a problem includes pressure inlet boundaries; use pressure outlet boundary conditions (see Section 7.3.8) instead.
b.) If you are modeling compressible flow.
c.) If you are modeling unsteady flows with varying density, even if the flow is incompressible.
d.) With the multi-phase models (Eulerian, mixture, and VOF (except when modeling open channel flow, as described in this section in the separate Theory Guide).
But, if some used it for modelling multiphase flow (gas-solid flow through a pipe) what will happen?????

2.) If the value of gauge pressure is not known at the outlet only gauge pressure at inlet and velocity for both phase at inlet are known, then what value of gauge pressure for pressure-outlet boundary condition be used for simulation????

Thanks..