Boundary condition on 3D Supersonic nozzle problem with atmosphere
 

Hello :o

I try to solve an unsteady problem that supersonic nozzle flow(from the combustion chamber) impinges on a gas deflector.
During the solve this problem, there are thousands cells under 300K, and under 1000Pa.. and it's doubful if this problem goes well.

I have 3D grid(L x W x H : 30x10x35 in meter) that has symmetry. 2 species(hot gas and air) for material and the hot gas has Cp which is function of temperature, 26 for molecular mass, other is ideal or constant. air is.. air with ideal gas properties. Here is my BC setting..

- nozzle inlet(combustion chamber)
mass flow rate : 300 kg/s
supersonic/initial guage pressure : 101325Pa
total temp : 3900K
- atmosphere(pressure farfeild)
Mach # : 0
guage pressure : 101325Pa
temp : 300K
- wall
nonslip condiiton for moment
adiabetic for thermal condition

Initial conditions are 300K, 101325Pa

I set the under limit as 300K for T, 1000Pa for static pressure