Hello Reno,
I can confirm my mesh is watertight and conformal with the solid body.
I have just tried to run it with Tethaedrons (triangles) and it seems that it has meshed successfully! However, the running time for the ICFD-only is still very low (2e-6s steps every 3min for a 80,000 elements on the surface mesh). Can you confirm this run time should be expected for an engineering-prepared workstation? Maybe there is still something wrong?
On the other hand, my LS-Dyna version is R11.2. It is good to know that future versions can locate the error, but unfortunately, license is provided by my university and I am afraid I can't ask for a newer version.
In any case, are these runtimes common?
Now that at least I can run the model, I can keep working on it. Thank you very much for your time and help in this, it is very much apreciated!
I hope you have a great day.
Arnau