[donalffons]

Hi everyone!

I'm a beginner with Ansys / CFX and after completing a bunch of tutorials and doing some simple analyses, I am struggling now with the following problem:

I want to simulate the rotation of the pistons of an axial piston pump (like this one). For simplicity, I broke down my problem to what you see in this picture:

The point is to simulate, how the rotating parts influence the fluid. The goal is to find out, how much drag force is created by the system. Until now, I fail to set up the system in CFX-Pre.

I tried several things here:
- Stationary fluid domain & rotating walls: This doesn't work, because the walls are not allowed to have normal velocity components
- Rotating fluid & stationary / rotating walls: I tried around with some boundary conditions, but the results were always not as expected
- Immersed solid (and a different mesh): This worked, but the results were quite incorrect. For example, I got result forces in X-Direction

So, I'm lost here. Can anyone give me a hint on how to solve this? Or should I take a somewhat different approach?