[qusaimn]

I am performing a CFD study to analyze the effect of different swirl numbers on the shock structure in a CD nozzle.I have been trying to simulate the shock for very long time.I have obtained satisfactory results for over-expanded flow in the nozzles with and without the swirl, however when i try to simulate the shock the solution never converges(flat line with oscillating residuals). I have tried a lot of stuff from changing the turbulence model to changing the under relaxation factors but to no avail.My mesh quality(created using ICEM) is pretty good and has close to a million nodes.I am certain the mesh is not a problem.My BCs are ,inlet pres=1atm and outlet pressure is 65kPa.I have attached the convergence map(outlet pressure at 45kPa).Any guidance will be of great help.Thank you in advance!