Reply To: Specifying the pressure at pressure outlet boundary in multiphase flow

[Rob]

You may have a problem with the inlet depending on flow velocity and acceleration under gravity. Have a look at the flow of water out of a tap. Is the jet/column of water uniform diameter all the way down? Ignore spray or twisting effects in the flow. 

The second model may also not behave as you'd like. With a fixed flow in and out the liquid level will both determine the hydrostatic pressure on the other outlet but also becomes part of the solution: that may be unstable, and the end solution may be full or empty. Think carefully what the point of the model is, ie what you are trying to find out.