I'm trying to determine the exit behavior of a converging-diverging supersonic nozzle. To do this I want to set up a simulation so that the exit boundary condition is standard atmospheric conditions. I then want to view the particle trajectories passing throught the exit to see if they are over or under expanding as they exit. Unfortunatly, the streamlines all seem to stop at the exit where I set up my boundary condition, is there any way around this?

Thanks