boundary condition for two phase flow
 

Hello everyone,

I am trying to a 2D simulation as the image described, gravity was considered, obviously the pressure outlet boundary did not work well for this problem.

Is there any way to define a Neumann boundary condition at the outlet, like ∂p/∂x=0, ∂v/∂x=0, or other way to simulate this correctly.

the easy way to do it well is to use the vof flat wave method in star and then use the special pressure outlet hydrodynamic pressure field that is created