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MRF : divergent flow near interface when the rotating zone is unaligned

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Old   March 16, 2022, 06:39
Default MRF : divergent flow near interface when the rotating zone is unaligned
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Hello!
When simulating a wind turbine with unaligned flow (turbine with tilt) I got a divergent flow near the interface of the non inertial zone and inertial zone. (Image1)
Im simulating in a steady flow regime (simpleFoam) with MRF (multiple reference frame), when the turbine is aligned with the flow the flow is fully converged. (Image2)
I have set the patches excluding the blade patches as non rotating patches in MRFProperties.
I had tested in three different meshes with different refinements in the interface (57MM cells in A mesh, 62MM cells in B mesh, 97MM cells in C mesh) to better achieve an interface weight in AMI. But the three meshes diverged.
For a last attempt I simulated an unaligned flow in an aligned mesh, changing the velocity components, but diverged as before.
The mesh is a cylinder 15 diameters long and 5 diameters high. Inside the mesh there is a cylinder 2 diameters long and 2 diameters high, which is the rotating zone.
I don't have a small example, this link contains the results and the mesh: https://drive.google.com/file/d/1Rqz...ew?usp=sharing
Openfoam v2006, gcc v8.3, centos.
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File Type: jpg image2.jpg (30.9 KB, 10 views)
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Old   March 17, 2022, 10:47
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See this old thread and the excellent explanation of Eugene here: Should an empty MRF zone really induce this much cross-flow?
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Old   March 30, 2022, 09:43
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Thank you for the explanation
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mrf, simplefoam, tilt, wind turbine

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