Convergence difficulties
 

Hi everyone!

I have an issue regarding the convergence difficulties in Fluent. My case is 2d axisymmetric single stream nozzle. The mesh I was given and its quality is good. I use k-eps model. My solution converges with inlet velocity 1 m/s (pic1) and I can suppose that mesh is fine, but when I set inlet velocity to 10 m/s or higher fluent doesn't converges it (pic2). :(

I tried several attempts to fix it but still haven't found the solution. Maybe some of you guys has experienced it or knows how to deal with that?

Thank you!
Really appreciate your help!

Hi!

Have you checked the y+ values?

Thank you for your reply!

On the picture attached my Yplus values after converged solution at inlet velocity 20m/s.
I'm trying to increase the speed as I have to end up with Mach 0.85.

In order to refine the grid I adapted Yplus values (30<y+<60), however I'm still struggling as my solution is not converging with increased velocity and Yplus seems to be at the desired range