Hallo,

I'm trying to analyse a simply convergent nozzle. I do not know if the flow becomes supersonic (probably no, ptot-in is 1.5*ptot-out).

I would like to know what is supersonic pressure in pressure inlet boundary condition and how I can estimate it.

Thank you very much

Giacomo

In my opinion, supersonic initial gauge preesure is used for initilazation under solve initialize. And in case of a closed supersonic area in the flowfield, where the information from the outlet can not go back to the inlet, it is used as staic pressure at the inlet.

For convergent nozzle the flow will not be supersonic, by using the compressible flow tables of 1D flow you might estimate the Mach number according to the contraction ratio..good luck.