Pressure boundary condition and real gas

Pifou

Hello,

I have modelised an high temperature real gas passing in a large nozzle (about 80cm length and 5cm diameter) and discharging in an atmospheric pressure volume. The injection of gas is a lateral injection with a vortex component. I have used the user real gas model, an inlet pressure of 1.1atm in the nozzle and an inlet pressure of 1atm for the exit volume. The flow is laminar. In the volume, very strong waves appear in the field of velocity which is not really "normal". I think that it's come from the coupled model which not seems to really work with this kind of boundary condition. Is anyone has an experience of this kind of problem?

Thank you very much

Pifou

I have imposed two boundary conditions