Hi all.
So I have run into an odd problem with a FSI problem. The actual set-up of the problem is relatively simple, a pipe filled with water with a free moving piston head at either end keeping the fluid in the pipe. Thus when one of the pistons is moved it should force the other one to move as it transfers the force through the fluid between them.
I can the model to solve for ~0.2 seconds of the 1 second time dependant study I wish to perform but at that point I recieve a warning about an inverted mesh element and the study fails with the following error message:
"The following feature has encountered a problem: - Feature: Automatic Remeshing (sol1/t1/arDef) Recoverable error in residual, but solver could not recover. Time : 0.245 Last time step is not converged."
Inspecting the mesh shows that the mesh elements in the corner of the fluid where the piston touches the wall of the pipe do not move at the same speed as the prescribed normal mesh displacement assigned to the face of the piston. Even when reducing the time step this problem remains. I've also tried increasing the mesh quality. Pictures attached below using a rough mesh just to show the effect I ma talking about.
If anyone has run into something similiar or has an idea to try that would be much appreciated!