Problem with IQN-ILS in the Calculix Adapter(FSI)

Hi, I have recently been trying to compute the tureK-Hron case using OpenFOAM and Calculix coupling. And I also refer to this website: tutorials/precice-config.xml at nithinadidela-patch-1-Turek-Hron1 · nithinadidela/tutorials · GitHub . When I set , it can be calculated. But when I change to (OpenFOAM and Calculix have also been changed accordingly), Calculix calculations show the following error. I don’t know why this problem occurs. Maybe there is something wrong with IQN-ILS Settings. Can someone help me? Here is my case file.
PreCICE: v2.1.1
OpenFOAM(org):7 (436.0 KB)


I’m not familiar with this case in particular, but maybe you should try with Aitken acceleration. It’s simpler to configure than IQN-ILS and should converge. (though slower)
Then, if something is wrong in the case or the adapter, we should have a proper output to examine.

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Thank you! I think the reason might be that the speed was small at the beginning of the calculation, because here I increased the speed from 0 to 1.5 m/s in 2 seconds. This problem does not arise when I compute a few time steps for the fluid domain and then couple it to the solid domain. Maybe next time I can try changing iqN-ILS to Aitken Acceleration, because I think IQN-ILS has a better convergence.

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Yes, IQN-ILS is usually faster, so if you can make it work it’s probably worth it.