Hi, I suppose to see air exhaust from both ends of a open- end channel by natural convection. If flow from left to right (+x direction) with very low velocity. Boundary condition at the left set as velocity inlet . And right end is prssure outlet.

Is this right Bcs. for reversal flow occuring?

Thanks very much!!

I don't think you can have backflow out of a velocity inlet. You should probably be using two pressure inlets.