Periodic displacement // Moving Mesh
 

Hello.
I have a little question regarding the periodic displacement of a moving mesh.
Im working with the ValveFSI.cfx file form the Ansys tutorials.

What I am trying to do:
Let the ball move through the Valve.
Transient solution for 7.5e^-3s

What I did:

1. Using a UDF (A/2*cos(omega*t)) with a frequency of 400, in mesh displacement of the ballmesh
=> I got negative Volume elements and sectors (I checked physic and tryed to fix it but it didnt work yet)

2. Use the periodic displacement, same conditions as 1.
=> Problem: Periodic displacement always works in both directions (what does the x,y,z displacement for normalized coord mean?). So if I want the ball to have an Amplitude of 0.0075m (almost at the top of the Valve) it goes back to the origin (when it didnt fail cause of negative elements) and crashes the bottom tank.

3. Use the rigid body solution.
=> kinda bad cause i have to guess the displacement since i dont have a force, i have a strict point where the ball has to move


My main problem is the debugging of the moving mesh (already searched for it but couldnt fix it)

Can anyone help? I would appreciate it =)