[Zackzack]

Hello there.
I am currently trying to simulate the pressure distribution in a Squeeze Film Damper in Ansys Fluent. I am getting good and steady results when i am calculating with big time steps or a very low fluid density, however, if i try to use small time steps (dt=1e-5 s which is not unreasonable for a SFD) and a realistic density the calculated pressure field jumps around like crazy. It completely reverts from time step to time step or five folds from time step to time step. I already tried to lower the neccessary residuals, used more iterations per time step, but to no avail.
The configuration is similar to a hydrodynamic bearing, except the journal is not rotating, it moves translatory in a circular orbit. So the Lubrication Gap is constantly deforming, i am using a dynamic mesh with a profile file to move the inner border. The adjacent zones are deformed with spring smoothing. The mesh element distortion is relatively small. There is a pressure outlet on one side of the domain and a symmetric border condition on the other side. The Model is viscous - laminar and i am using a structured hexahedral mesh with 10 Elementes in film thickness direction and about 400 in circumferencal direction.



Does anybody have an idea what could be the cause?