What is the Difference between a rotating Zone and Rotating Wall?

Using SimScale
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I have been attempting to simulate a ducted fan at high speed rotation 2000 rad/s, with the fan blades as rotating walls. however the result does not look correct to me. what is the What is the Difference between a rotating Zone and Rotating Wall in a steady state simulation with compressible flow? also which should I use.

Thanks in advance

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Hi @swinkelstein!

Afaik rotating wall is intrinsically unsteady whereas MRF is for steady-state behavior without a mesh motion and there are known issues with MRF or “limitations” for the MRF approach. Can you share the project and tell us what values you would expect? If you have data that would of course be the best :slight_smile: And please let us know what you mean with not correct (artifacts? orders of magnitude off?).

Cheers,

Jousef

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Thanks @jousefm for the for the description. The main thing I was expecting is a high air speed through the duct. none of my simulations are showing this.

here is the link to the project

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Hi @swinkelstein!

Okay from what I can see the boundary conditions can definitely be improved and I also assume that the size of the domain acts as a blockage for the flow influencing the surroundings of the fan. Also do you expect the flow to be above Mach 0.3 or is there a specific reason you want to have it compressible?

Cheers,

Jousef

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