boundary with pressure jump
 

I need to impose a pressure jump in a boundary, i. e. a pressure drop as function of flow rate in a extrude that I don't want to do geometry/mesh. I can impose that in internal faces with porous jump. Does someone knows how to do it in a boundary?

Try the outlet-vent boundary condition.

Thank you. It seems to be the BC I need. I need to impose a pressure drop as function of velocity, but I just found how to set the "loss coefficient" polynomial, i. e., dp=(k1+k2*v+...) rho/2 u^2, so it doesn't have just the "linear" dependency of u. There is some solution to that?