However, when I change it to free slip adiabatic for top and bottom and use
domain initialization the same as the inlet.
I get the attached results with the residuals moving in 1e-8 to 1e10 range and goes on until the heat transfer and turbulence converges!!!!
however the heat transfer and turbulence ones seems to converge.Attachment 32245

Attachment 32246

Attachment 32247
Thanks

I did that and sent you the CCL file
Thanks

Ok, so what is the problem?

Is it ok that it is over converging?
Does it mean it is already converged in terms of momentum?
SO there is nothing wrong with that?
So for transient simulation, I should just change the analysis type and keep the rest as before?

Over converge? Never heard of such a thing.

Steady state is working.

Transient should work just fine. I have done many of these problems.

Typically I model a large caliber gun blast and blow down. Pressure wave travels just fine.

It was a made up word. sorry.
I meant what does it mean when you set your convergence criteria to 1e-6
but the momentum components are converged from the beginning of the run like this case?
It seems to be running for now, hopefully it won't fail.
Thank you again.
Best,
Hesam

Dear Edmund,
The flow in a channel went ok. however, back to my original problem, supersonic flow over a forward-facing step, my steady state run diverges and fails after 120 iterations. I used the same BC for this problem and just defined no-slip BC on the step surfaces. I have attached the geometry and the CCL file. I would appreciate if you could take a look. the velocity is 1041.84 at the inlet corresponding to M = 3 and the domain initialization is the same as the inlet.
thanks,
Hesam

I would guess that your Boundary conditions are too close to your step. For sure, a shock wave is hitting that step, reflecting back and hitting your opening.

Move the BCs further away.

Also, turn on high speed numerics. its under solver control.

Dont use Auto Timescale. Use a Physical One, for starters you can try L_characteristic/U, or use Local Timescale first then switch to Physical.