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Elvis April 19, 2006 17:00

discussion about MRF/moving mesh from Fluent forum
Moving reference frame (MRF) analysis yields to wrong analysis conclusions all the time.

To compare with experiments the data from RANS-MRF are time-averaged but many young cfd engineers do not add the 'location-averaging' of the rotating part bfore comparing and it is not comparable because the geometry is moving. This is one main mistake.

Then when you compare, RANS+location-averaged with time-average experiment, it is off 90% of the time.

The reason: the moving mesh simulations also capture secondary flow fields that are transient, that MRF misses totally and even propose totally different results.

as He said, MRF is effectively only good for intial field for a moving mesh run.

What is you experience?

Vincent April 19, 2006 23:25

Re: discussion about MRF/moving mesh from Fluent f
I also got the same problem... I used moving mesh to solve a heat transfer problem...The results show that the temperature in the friction area is even lower than that of the coolant which is supposed to cool the friction heat generation...This is very much wrong obviouslly. However, when I used moving mesh, the temperature looks reasonable...I don know what is the real difference between moving mesh and moving reference frame...

the strangerers April 21, 2006 16:30

Re: discussion about MRF/moving mesh from Fluent f
MRF: the mesh is static, source terms mimick the rotation

Moving mesh the mesh is rotating each time step.

Some people still use MRF for rotating machinery?


Vincent April 22, 2006 11:08

Re: discussion about MRF/moving mesh from Fluent f
Sir, Thank you for ur reply.... Thanks a million... U don use MRF for rotating machinary? What r u using ? I used MRF to simulate some temperature profile in the interface of the rotating, the results is totally wrong...But when I use the moving mesh, the results seems the same as those without rotation.... What do u suggest for this? Thanks a million....

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