moving mesh and sliding on a boundary
 

I want to simulate the fluid flow around a stable cylindrical boundary when a block oscillates on this boundary.

At first I used solidBodyMotionFvMesh but I found that the boundary moved with the block.

If I use mixerFvMesh, I don't know how to set up the dynamicMeshDict file because the sliding interface is boundary and there isn't the stable fluid zone.

Can someone gives me some suggestions? Thanks a lot!