Problem for negative cell volumes and float point exception with overset mesh
I am simulating a planing boat with overset mesh (I gave up triying with moving deforming mesh). The simulation has a strong fluid-solid interaction. I generated the overset mesh already with no orphan cells and was able to simulate with a still boat. However, when I activate the dynamic mesh and assign the rigid body features with the udf and start running the simulation, it fails at a low number of iterations, say 200-300 (I need more than 50.000 iterations). The usual messages are "Floating point exception", which I understand is due to high unstable pressure formation around the hull so the forces soar up to infiite values, or "Negative cell volume detected", which I understand is because the time-step size is not large enough to allow the mesh to be updated before a cell pierces another cell, or because of a bad quality mesh.
I have tried setting the mesh implicit update every iteration, up to 50 iterations per time step, with a time step of 0.001 seconds, reducing the relaxation factors, activating solution stabilization for the pressure, triying with lower flow velocities (5 m/s) but nothing seems to work. This settings in fluent, makes me thing that is a low quality mesh issue, though I have triying refining and reducing high skewed cells with no positive results.
I am using polyhedral for the overset mesh around the hull and cutcell hexahedral cells for the background mesh, I attach a picture next. Note that the domain is very small because of low computational resources. I have seen everyone which simulate planing boats, use the same type of mesh for both the overset and background domains so a question arises: ¿Is it easier to achieve a smoother mesh motion and convergence in the calculation if both meshes have the same geometries for the purpose of simulating with overset meshes?
I also attach pictures of some monitors for pressure, lift and drag forces, momentum and some mesh motion variables. It seems the boat sinks (as expected), but rotation around CG_Z is zero (should be greater than zero).
After the simulation failed with "Negative cell volume detected", I plotted in the posprocessor isosurfaces with "cell volume error" and "low quality cells". I attach some pictures of that result too. The low quality elements have minimum ortogonalities of 0.08-0.1, which should be enough to perform the calculation.
Help! it was supposed the overset mesh was easier to setup than the moving deforming mesh