[samuelnobrecg]

Good morning,

I am trying to simulate a pitch decay test of a 3d-hull with symmetry to reduce the ammount of cells. I am using rigidBodyMotion solver for the dynamic mesh and limitind the only degree of freedon to rotation in Y direction. I run the case until 0.01s and then apply an angular velocity of 0.05rad/s with a timestep of 0.01s leading to a Courant number of ~0.3. However, the mesh update seems to crash when reaching 0.37° of displacement at 0.26s and it also happened for different refinement levels and different timeSteps/Courant numbers.

This crash is different from the common crash due to bad setup of inner and outer distance in dynamicMeshDict since it happens at a low displacement and squishes the mesh in a strict region, losing the hull local geometry and also deforming the mesh in the direction normal to the symmetry plane.

My masters project is still ongoing so I can't share the mesh or full geometry of the hull but I can share the case setup and a screenshot of the region before and after the sudden deformation. The mesh was generated in Ansys Mesher with ~1.3kk cells where the closest layer of cells have 0.1m of thickness.

I am not familiar to adjusting the numerical parameters in fvSchemes and fvSolution, so I am using the default values of the floatingObject tutorial. The same setup worked fine for a 2d case (without symmetry) for roll decay simulation. So I guess that it has something to do with the interaction between the mesh recalculation and the symmetry plane.

I would like to know if anyone has faced a similar problem or has a clue of which parameter should I focus on adjusting to ensure the stability of the mesh recalculation to avoid this type of mesh crash.

Thank you for the attention!

Samuel