Rotating Vanes in Air -- Detected divergence of the linear system solver


I was able to run this to successful completion at 200 radians per second (rotation zone), but when I went up to 600 radians per second (with everything else exactly the same), I continue to get the following error. I tried lowering the relaxation factor for p, and also changed the mesh down from 8 to 5, but I get the same error. Any further changes on my part would just be trial-and-error type approaches. Thanks –

Detected divergence of the linear system solver. Consider lowering the relaxation factor for field p.
The solution diverged, please check your simulation setup. Divergence can also be caused by bad elements in the mesh. Such elements tend to exist near walls and sharp corners. Visually inspect your mesh to locate them and re-mesh with additional refinements in their vicinity. If you are confident about the mesh-quality, please reduce relaxation factors and use more conservative numerical schemes.

Hello spquinn,

thanks for reaching out to us here in the forum.

Can you please share a link to your project with us, so that we can have a look at your simulation?

Best regards

Thanks Sebastian. The project is public, and I shared it with you, SBlock. But you said, “share with us.” Is there a way to share it with this forum instead of by user or email?

Here is the link to the project: SimScale

Hello spquinn,

having a look at you 200 rad/s case I notices that the max velocity is at around 90 m/s.
We suggest that for incompressible simulation the velocity should not exceed mach 0.3 (103 m/s).
So this case is already pretty close to that suggestion.

Therefore I would suggest switching to the compressible solver.
Also i would suggest ramping up the rotational velocity even for a steady state simulation.

You can do this via table input to your mrf.

I would suggest ramping up the rpm within the first 500 iterations and simulating the further 1000 till 1500.

Please let me know how this worked for you.
Best regards

Thanks for the advice, Sebastian. I will try the compressible option on this and ramp up as you suggested.