Reply To: Tutorial or Help for 2 way FSI

[Paul Hutcheson]

Hi Ashish,

Reversed flow is flow either coming into the domain from an outlet, or flow going out of the domain at an inlet. It's not necessarily a bad thing.

The floating point error is most likely a symptom of divergence, possibly from poor mesh quality. You need to be monitoring mesh quality as the mesh deforms. If the quality is deterioating too much the solver won't converge. If quality becomes poor you need to check the dynamic mesh setup and monitor how the mesh is deforming. Maybe you need to allow the mesh to slide on some walls adjacent to mesh motion. I can't comment further without seeing how the mesh is deforming.

As for why the IR is not rotating, is it being rotated in Mechanical? I don't see any boundary condition applied to it. For rotating machines, we recommend rotational velocity, which will solve the IR in the rotating frame, but not move the mechanical mesh. On Fluent side of IR, it's probably best to set the wall velocity according to the rotational speed of IR and receive just the normal displacement from Mechanical.

Also the ball seems to moving across the symmetry plane, you need a symmetry boundary condition there.