Currently am modeling a section of duct with several features present within the flow stream including a porous screen. I want to mesh the inlet as a 'Mass Flow Inlet' BC so compressibility effects can be accounted for, and a 'Velocity Inlet' BC is not possible for this. The duct expels into the atmosphere in a plume. The outlet BC is modelled as a 'Pressure Outlet'. When solving I get a "Floating Point Error: Invalid Number" message. When going to a velocity inlet it will solve fine. Is there an incompatibilty problem present?

of course, boundary condition muss consist with physical property of the flow, mass flow in--mass flow out or velocity out pressure in--pressure out or velocity out

if you are given mass in, but pressure out, it is extremly difficult to resolve for pressure at inlet, or velocity at outlet;it is almost impossible, not that i know