Hi... I deal with converging-diverging nozzle(ISO 9300).

solution : 2D-compressible, steady-state, laminar

1) Nozzle throat diameter(d) = 4.48mm, inlet radius = 2d, nozzle length = 7.43d, nozzle expansion half angle = 4 degree.

2) Boundary condition : *Stagnation(upstream) : P=2e+05, T=20, direction=normal *Pressure(exit) : open air(P=0) *Symmetry *Wall : Np-slip

3)Thermophysical..... *Molecular Properties -density = Ideal-f(T,P) *Turbulence off *Thermal off *Refference data : press=1e+05, temp.=273, Cell NUmber=1(inlet point)....

there is no convergence after 1000 iterations.

What is the problem? Please, teach me. Thanks.....

Check your Reynolds number. I guess you should have turbulent flow. Also you can reduce the Relaxation paraeters and check