Difference between MRF and RBM
 

Hi Everyone, I am new to Star CCM+, What is the difference between moving reference frame and rigid body motion. Except the difference like moving mesh in RBM(unsteady), stationary in MRF(steady).May i know what are all the other difference.

I will give this a try.
In MRF the different bodies are fixed in position but the fluid feels the forces as if the bodies were moving. This will often be good enough for axisymmetric geometry.

in rigid body motion the reference system stays still, and the domain/flow/mesh is moving.

in mrf, as the name suggest, the entire system is moving. because this method is less computationally expensive than the rbm, it is successfully used in, for example, rotating parts, turbiles, isolated propeller analysis (in case of a rotation)

hi ...
do u know how to use reference frame in turbine analysis
need to know ,the turbine RPM given the mas flow rate as input

thanx

sorry to disappoint you, but I belive that to get the rpm you'll need to use the RBM tecnique

thanx for replying ...
can u plz elaborate ,about RBM techinqes cuz i have not used that one so far...
thanx a gain

I'm sorry I have to disagree. It's just a matter of accuracy and computing time whether to use RBM or MRF. You'll get a (less acurate) result using MRF, but it might still be better than a bad RBM result.