mass flow and pressure BC known at inlet, outlet BCs unknown
 

Hello,
I wish to analyze a compressible flow through a bit complex geometry.
I know my mass flow rate and pressure at the inlet.
Boundary conditions at outlet are not known.
I can't use outflow boundary condition as the flow is compressible.
Hence, I am unclear about the selection of the inlet and the outlet boundary conditions.

If anyone knows how to solve this or faced similar situation, please help me out.

Cheers!

Mass flow inlet with static pressure specification

Pressure outlet at the outlet