Inverse degassing condition?
 

Hi all,

I'm trying to model a gas/liquid cyclone with liquid loadings up to 20%. Hence the gas will be the continuous phase in all cases. In the bottom part I have a fixed amount of liquid, so I can use rho*g*h as a pressure boundary condition at the bottom outlet.
At the top outlet I'm looking for some kind of inverse degassing condition. I want this outlet to behave like an outlet for the continuous phase (gas), but the for dispersed phase (liquid) it has to behave as a (free slip) wall. The standard degassing condition is only able to do the opposite (outlet for dispersed phase and wall for continuous phase).
Could anyone tell me if this is possible? Any other recommendations on the boundary conditions are welcome as well.

regards,
Boris