sonic outlet
 

What are the best boundary conditions for converging nozzle flow with sonic outlet?

Please refer to the characteristic boundary condition for Euler equations.( test book name: computational fluid mechanics and heat transfer edited by Richard H.Pletcher Chapter 6 section 7).

thanks for your reply. but I didn't find anything about sonic outlet.

I know about supersonic or subsonic outlet. "Sonic let " means the velocity at the exit is the exact sound speed ? Is that what you mean?f

If yes, there's nothing special other than supersonic or subsonic conditions. And if you are performing a CFD code, any appropriate boundary conditions could lead a pleasing results. I have done tests for both exact boundary and characteristic boundary. If you are conducting an experiment for nozzle flow, total temperature, total pressure and velocity will be needed because the three variables is easy to measure in real world. Besides, for transonic flow with shock, you may need an extra condition.

Hope it can help you.