Have a frustrating problem with a simulation involving a rotating cup mesh containing fluid. The collision appears out of sync and is worse with increased velocity.

I've already solved most of the collision issues (I think) by increasing both voxel density (using particle separation of .01) and simulation substeps.( using 8 currently).

The cup in this case is an inverted pyramid.

The motion is oscillating rotation in y axis, think ‘washing machine’. The attached Top View mp4 should make this clear.

Something to do I assume with the velocity of the collision vdb(cup) being passed to the fluid particles or…?

Anyone care to diagnose what is happening?