dynamicMesh case setup simpleton questions
 

im trying to set up a dynamic mesh case for a ball free falling in a box. the geometry is simple but I'm confused as to how to specify the ball. is it a "cut out" of the box geometry, or simply internal "faces"?

if I understand correctly, the "pointMotionUx" files are were I would then specify the movement of the ball, but do I also need to specify the movement in the U file?

If the ball itself doesn't need to be simulated (e.g. no heat transfer in the ball), you can cut it out of the domain and set the generated boundary as a moving wall.

You will need to change the mesh topology throughout the simulation as the ball falls. Depending on how you mesh your domain you can either use layerAdditionRemoval with something like the movingConeTopoFvMesh, or use fvMotionSolver dynamic mesh and remesh the domain when the mesh quality deteriorates.

Thanks for the tips. I got the simulation to run although I'm not sure where to account for the effect of gravity. Is there a tutorial that deals with free fall?