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rotatingWallVelocity vs. SRF vs. MRF vs. AMI/GGI

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Old   September 10, 2012, 19:14
Default rotatingWallVelocity vs. SRF vs. MRF vs. AMI/GGI
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This is a fundamental question that I need to think it through. I'm trying to model the flow inside the attached geometry. The mill (in white) rotates at a constant speed inside the casing (in red). The casing is a simple cylinder, and the whole system is filled with a single-phase liquid. Also, there is not protrusion on the outer surface of the rotating mill/shaft.

Can I simply model this using rotatingWallVelocity and say, simpleFoam? Would it automatically take care of the coriolis and centrifugal forces? (Notice that I will be modeling this in 3D). Also, considering the holes on the mill surface, would these methods work, or do I need a more advanced dynamic mesh method? Any thought/suggestion is highly appreciated.
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Old   September 11, 2012, 13:12
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Presumably the casing is stationary? Since you have only one moving domain and there are no baffles on your stationary cylinder (as near as I can tell from the image), there is no need for AMI/GGI. As you suggested, I think rotatingWallVelocity might barf because you have the holes in the rotating part--it is worth a try, but I think it wants to put just a tangential velocity on the surface which is not valid for the interior of your holes. SRF or MRF should have no problem at all. If there is not already a solver available, it is not too tricky to add in MRF capability to simpleFoam or whatever you will be using.
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Old   September 12, 2012, 12:58
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I think rotatigWall will give bad results. I would use MRFSimpleFoam, but I would cut the domain into several domains very close to the plates. This would be the most accurate solution - if it is a steady phenomena, of course.
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Old   September 12, 2012, 14:19
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If there are no baffles on the stationary part, then whether it is one rotating domain or multiple as Attesz has suggested should give the same results.
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