[indy07cz]

Hello foamers,
I'm solving a stepped chute with spillway in interFoam. Mesh is about 1mil cells and checkMesh is OK. But I have some issues with BC for atmospere and outlet. After few seconds simulation blows up due to unreasonably high velocities (from 100-500 m/s) in air phase at corner cells (see attached pictures), water phase is ok.

BC are set like:
atmosphere
--------------------------
U: pressureInletOutletVelocity
p_rgh: totallPressure 0
alpha: inletOutlet

outlet
-------------------------
U: inletOutlet (zeroGradient blows simul. much faster)
p_rgh: fixedFluxPressure
alpha: zeroGradient

Simulation works fine only when I set p_rgh at outlet to totallPressure 0.
I set proper initial conditions, but I don't know why is velocity increasing. Any tips please?

[indy07cz]

Well after some thinking I was able to find a solution myself.
There should be outlet BC for p_rgh inletOutlet instead fixedFluxPressure.
Maybe it will help to somebody in the future.