I am aware of the simulation not needing to reach the prescribed convergence criteria but for some reason my simulation is diverging on the last grid level and I have exactly applied all the correct settings for the simulation, paid attention to make the blade and hub rotating while the shroud is static. My mesh looks exactly as it should be (photo attached with quality statistics).
I really don't have any answers for what's going on, maybe there is something I could check that I am not aware of right now?
I was able to prevent a crash by applying residual smoothing, but this was not one of the suggested settings so there still might be an error somewhere in my setup. Atleast I am able to already analyze some results right now, even if they might not be 100% correct(mass flow converged well though this time).
good you mentioned the point that you are aware of the meaning of the warning message. Good also you tried the setting with the residual smoothing yourself! I double checked the settings and the domain setting in the numerical tab should be:
I was wondering whether we missed that setting when we created the hand-out.
In the hand-out we only specify the settings, which need to be changed compared to the default settings (with only a few exceptions). After investigating the case a bit further, I noticed that the default settings potentially can vary based on the mesh input. In this case you would have these settings, which I assume you got:
Explanation for the different default settings
When you create a new simulation setup, you choose a solver and add a domain. At this point of time the recommended default settings are set based on:
If no grid is present at this point of time, the general default settings with CFL=1.5 (CFL=1 for CGI) and deactivated residual smoothing are applied. If for challenge 6 the mesh is present, Omnis detects that a structured Autogrid is used for domain 1 and uses the recommended default setting with CFL=3 (CFL=3 for CGI) and residual smoothing activated.
What to do now?
Please excuse this issue. We did not see this coming, but will note it down for the next round of the CFD Online Course.
thank you very much for this detailed answer.
This must be the problem, because as you say the default settings are different in my setup and look exactly like in your second screenshot.
I will apply the correct settings in the numerical tab which should certainly fix my issue.