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-   -   STAR-CCM Rotating Wheel Simulation (https://www.cfd-online.com/Forums/star-ccm/239931-star-ccm-rotating-wheel-simulation.html)

jswift December 2, 2021 20:55

STAR-CCM Rotating Wheel Simulation
 
Hello,
I am working on a CFD project analysing the flow around a rotating wheel. I have previously conducted simulations using a simple cylinder model using rotating boundary conditions and the 'rolling-road', and I am now looking to rotate the inner rim/spoke section. I have imported 2 separate models, the inner rim and the tyre extruded at the base, which sit just inside each other (no gap). The tyre is subtracted from the domain and automated meshes are created for the subtract and the rim, with the rim mesh set up to rotate inside the tyre.
I have tried zero-gap overset interfaces, interfaces between the 2 connected faces but continue to get an error saying 'Mesh may have non-positive volume cells, due to invalid imported mesh or errors initializing interface'. I have re-made the CAD models but continue to get these errors.
Is there something I am missing here? I have completed the basic turbine tutorials but they are made easier by the fact the blades are not in contact with the outer wall.

tundradot December 3, 2021 08:09

Are you using the automatic surface repair while running the mesher?

jswift December 4, 2021 20:45

I have managed to fix the mesh, there were some faults at the base as the wheel-base only just touched the floor of the domain creating an issue with the subtract.

I am now getting the following error:
"A floating point error has occurred. The following error has been logged: A on finite residual (X momentum) was added by star.segregatedflow.segreatedflowsolver. Typical causes are overflow, Check usage and inputs."

I have decreased the URF for the segregated flow solver and still get the error. Any ideas?

JBeilke December 5, 2021 13:54

2 Attachment(s)
The problem is, that your mesh runs into a very thin angle. You have to cheat a bit with your geometry.

jswift December 5, 2021 13:58

I have already made these changes and I still get this floating point error. I can only assume it is due to the contact between the inner rim and outer tyre, which just touch each other? But I have already set the interactions between the two.

JBeilke December 5, 2021 14:49

Just check the surface mesh (after remeshing). There is probably the best place to see the problems.

jswift December 5, 2021 17:07

Thanks all for your help, after checking the surface again I realised at some point I had started using an older CAD file. Cheers

RyGomes February 11, 2022 15:01

Hi everyone, I am doing the same simulation for my project and im trying to use MRF approach. I have just been riddled with errors when it comes to running my mesh. I did a stationary wheel study and it worked fine. now when I try to add rotation using multiple Reference frames its given me so many errors. I have gone through the tutorials on STAR CCM and haven't got a clue where I am going wrong. spent literally 2 weeks trying to make this work but with no results. its come to the point where I am literally in tears. could anyone help me out please?

the error im getting now is duplicate faces in surface mesh. I ran the diagnostics and there were no errors coming up. no pieced faces or whatsoever. the last few iterations I used surface wrapper and it was giving me errors so for this iteration I chose not too and it still doesn't work.


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