[K-al-Eps-o]

Hi.

I am simulating the flow inside and at the exit of a supersonic nozzle (convergent followed by a long straight tube - no divergent) using rhoCentralFoam.

My inlet BC is totalPressure = 5.00bar and the oulet BC is waveTransmissive = 1.01bar.
To take advantage of the geometry, I am solving the flow with axisymmetric BC. My domain is then a simple wedge - of less than 5°.
rhoCentralFoam is used as a density-based solver and the turbulent model used here is k-omega SST.

The issue I have is that the simulation evolves a lot between the first iterations, the iterations in the middle and the last iteration. Of course, I know rhoCentralFoam is a transient solver, but my system should be steady, when the right regime is reached. The solution I get seems to give me pretty good results according to experimental results at step 2000 but the solution at final step 38600 is far from the experimental results.

I attached figures showing the pressure gradient at step 2000 and step 38600 as well as the "numerical schlieren" and my experimental schlieren results.

Does anyone have a clue ?

Best