high-frequency oscillations Overset

acalado · December 5, 2021, 05:33

Greetings,

I am trying to simulate a simple 2D case of a flat plate at 45 degrees moving at constant speed (low Reynolds). I am using overset mesh grid with linear motion (constant velocity). Solver is overPimpleDyMFoam (v2012)

I have tried to validate the results and they seem ok in terms of order of magnitude, but there are some high frequency "noise" in the CL. I was wondering if anyone has any ideas on what may be causing this? I am attaching some pictures of the mesh and the resulting CL over time. I have tried to play with the numerics a bit (solution methods/tolerances/schemes) but no luck...

Thanks in advance!

louisgag · March 16, 2022, 14:52

Hi,
this is a typical problem from overset, in particular the openfoam implementation.
If you are using pimple, you can try to relax the final iterations, or setting momentumPredictor to false can also help. Be warned that the accuracy of your solution (continuity equation) may suffer, so use at your own risk..

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March 16, 2022, 14:52		#2
louisgag Senior Member Louis Gagnon Join Date: Mar 2009 Location: Stuttgart, Germany Posts: 338 Rep Power: 18	Hi, this is a typical problem from overset, in particular the openfoam implementation. If you are using pimple, you can try to relax the final iterations, or setting momentumPredictor to false can also help. Be warned that the accuracy of your solution (continuity equation) may suffer, so use at your own risk..