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high-frequency oscillations Overset

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Old   December 5, 2021, 05:33
Default high-frequency oscillations Overset
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André
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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!
Attached Images
File Type: png CL.PNG (84.1 KB, 21 views)
File Type: jpg mesh1.jpg (60.1 KB, 21 views)
File Type: jpg mesh2.jpg (74.1 KB, 18 views)
File Type: jpg mesh3.jpg (62.4 KB, 14 views)
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Old   March 16, 2022, 14:52
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Louis Gagnon
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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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