FSI with interFoam and CalculiX: Convergence

(moved from FSI with interFoam and CalculiX)

I am trying to solve the divergence issue with interFoam and CalculiX.
(FSI Flap case modified for interFoam).

I modified a few things with the OpenFoam settings and increased the time it takes for the simulation to diverge.
Initially ‘interFoam’ diverged way before the falling water column hit the flap.

But after these modifications, as soon as the water column hits the flap it diverges rapidly.
I have tried both, explicit and implicit coupling as well to try and increase the time at which the solution diverges, but no help as implicit diverges before explicit. (As per my understanding implicit should be comparably more stable than explicit)
Fluid_interFoam_explicit.log (119.3 KB)
Fluid_implicit_lastParts.log (78.6 KB)


Here, I tried reducing the water column size, but there is a similar results as above.

Any hints, advice are very welcome.

Thank you.

Edit: Here my OpenFoam files.fvSchemes.txt (1.2 KB) fvSolution.txt (2.0 KB)

I am using the following settings in controlDict:

maxCo           2;
maxAlphaCo      1;
nAlphaSubCycles=5;
maxDeltaT       1;

Could be just a very tough situation for the quasi-Newton coupling due to the sudden change.
Compare this post: IQN fails for quickly changing forces during wetting in a free-surface FSI problem

1 Like

Dear Alphaoo1,
did you modify the OF-adapter according the suggestions of Moaxm https://github.com/precice/openfoam-adapter/issues/127 ?
After this we received a good agreement for the elastic dam break (https://www.dhcae-tools.com/preCICE.html).
Best regards

Ulrich

Dear @Ulrich,
Yes, I did modify the OF adapter according to the suggestion of Moaxm.
And I was able to run the dam break case with the Help of Kyle Davis.

Later on, it was a matter of fine-tuning the Implicit mapping. :sweat_smile:

After this we received a good agreement for the elastic dam break (https://www.dhcae-tools.com/preCICE.html).

I actually started the work on this after looking at the LinkedIn postby DHCAE team. :grin:

Edit: Here I have posted the results.