Moving mesh - Particle moving through fluid

Fellow COMSOL enthusiasts,

I am trying to get familiar with COMSOLs moving mesh feature, starting with a really simple example: a particle moving through fluid (e.g. Stokes flow around a sphere). Normally one would of course keep the particle fixed, but I am curious how to implement this the other way around, using a moving mesh.

Any suggestions on how to do this in COMSOL?

Attached you will find two files:

1) Stokes_flow_around_cylinder.mph
This is with the particle held fixed (minor detail: it is actually a 2D cylinder rather than a sphere).
Only laminar flow is used here, combined with a stationary solver.

2) Moving_mesh.mph
My attempt on the moving mesh.
Laminar flow and moving mesh (ale) are used here, combined with a time dependent solver.

But... the fluid velocity remains zero everywhere! Shouldn't the no slip condition at the particle-fluid interface induce a velocity in the fluid?


Any help will be greatly appreciated!