Rob
Ansys Employee

You need to think through the application. If you move the bottom face, you will need to smooth the volume mesh. If you want the top of the domain to remain fixed you can't set it to be moving.  There are several videos on YouTube, including

  which explain various aspects.


The other point is what is causing the movement, and how far should it move? In a transient case the displacement is limited by the speed and time step: I have no idea how you would control this steady state.