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
Dear Micheal,
I hope you are trying to capture the flow behaviour when flow exits the C-D Nozzle and enters atmosphere.
Mostly flow tends to attain high velocity at exit of C-D Nozzle, Mach, 1.3>M<5 (in case of Supersonic flow).
As Conway suggested,
The exit area to be increased - To capture flow behaviour at atmosphere, also
The CV (Control Volume/ Control Domain) has to be extended in exit region of Nozzle
The Mesh settings has to be of very high refinement, inorder to capture High speed flows (like Mach > 1)
1. extend your exit area
2. use an internal/external analysis where your nozzle is in an external analysis and then you put a volume flow rate at the inlet to it and it expands outwards.
unless you use these methods, your flow trajectories stop at the outlet because that is the end of your computational domain