[roadRunner]

Dear all,
I'm trying to run a case of a buoyant flow in a vertical pipe using buoyantBoussinesqSimpleFoam. It's a 2D axisimetrix mesh (wedge), the wall is heated.

The problem is that at the outlet I'm getting unphisical reversed flow.
I'm currently using fixed U and zeroGrad p. for inlet
and fixed p, and zeroGrad U for outlet.
All other scalar transport eq. are set to zeroGradient everywhere.
I'm using kEpsilon turb.mod.

I'm also having some stability issues using this configuration.
What would be approprite BC for this case in your opinion?

I don't see what I could have done for U/p, and scalars should be zeroGradient, since they are unknown at the outlet. I was thinking of using inletOutlet for turbulence on outlet, to set the recirculating flow turb. settings, but that would be tampering with the solution.

Please help and thx