I don’t see anything useful in the log files. However, here are a few things to consider:
- One issue could be that the fluid mesh is getting too distorted. Have you checked the quality of the mesh just before it crashes? It can be that cells get too skewed or even too small (essentially collapsing). Different mesh motion solvers could help, but options are limited (and I think in the reference you used, they are using a special mesh motion solver).
- What kind of elements are you using in CalculiX? We recently discovered that it is very easy to get much better results using different types of finite elements: Change C3D8 elements to C3D8I elements in perpendicular-flap solid-calculix by AndresPedemonteFIUBA · Pull Request #250 · precice/tutorials · GitHub
- How do the results compare to Turek-Hron for the times you already have? Plotting the watchpoint (displacement of the tip of the flap) could help. I assume that you get higher displacement than expected, which makes everything worse.
By the way, @DavidSCN’s expertise may be helpful here.