Hi all, I am trying to set up a simple dynamic mesh problem. I want to model a 2D pipe in which a zone at the inlet moves upwards, which effectively closes the inlet of the pipe after a set time. I am using the in-cylinder model and I have prescribed identical rigid body motion for the walls and grid of the moving area and specified an interface between the moving and non moving zones. When I try to solve the mesh motion it Fluent gives me the follow message Error: Compute-node-normal: Degenerate faces. Can someone please advise me on the correct way to set up the problem. Thanks in advance, jim

What dynamic mesh model (layering, smoothing , remeshing) do you use? I think you don't have prescribe motion for grid, just for walls.