[npb]

Hello!
I am trying to simulate something like a stone falling down in a vessel. I use OF v2312, oversetMesh and sixDoFRigidBodyMotion without any constraints and restraints (because I want the solid object to move according to the flow). I include the libs (overset fvMotionSolvers) in the controlDict file. But the problem is that the object falls down and leaves the main domain. How can I make it "feel" there is a bottom? Maybe I should include some restraints, but I don't know what exactly.

I have another issue, which is related to the complex geometry of the main vessel. I use the adjustTimeStep and maxCo options, but the result is a very huge Courant Number and very small deltaT - smaller than 1e-20 or 1e-30. Is there any possibility to fix this besides making finer mesh, which would probably lead to very small deltaT again?

I would highly appreciate any advice!

Best regards!