Why the moving reference frames can be used for unsteady simulation?

Rinia · April 12, 2021, 05:35

Hey,

I performed a simulation in SATR CCM+ with the Moving Reference Frames, and found that the simulation can be solved by the unsteady simulation? In official tutorials, the moving reference frames is only used for steady simulation. Anyone could explain the difference between using unsteady and steady solver?

SESP · April 12, 2021, 10:33

Hi,

MRF is, in the classical understanding, an approach for steady-state simulations. In STAR-CCM+, you can combine MRF with an unsteady simulation, but its not time-accurate. So it doesn't make too much sense, actually. But it can still be a compromise, depending on the focus of our investigation. Theoretically, the only "real" unsteady simulation would be if you realize the rotation via rigid body motion or using overset.

April 12, 2021, 05:35	Why the moving reference frames can be used for unsteady simulation?	#1
Rinia Member Rinia Join Date: Jan 2018 Posts: 42 Rep Power: 8	Hey, I performed a simulation in SATR CCM+ with the Moving Reference Frames, and found that the simulation can be solved by the unsteady simulation? In official tutorials, the moving reference frames is only used for steady simulation. Anyone could explain the difference between using unsteady and steady solver?

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April 12, 2021, 10:33		#2
SESP New Member Join Date: Mar 2011 Posts: 22 Rep Power: 16	Hi, MRF is, in the classical understanding, an approach for steady-state simulations. In STAR-CCM+, you can combine MRF with an unsteady simulation, but its not time-accurate. So it doesn't make too much sense, actually. But it can still be a compromise, depending on the focus of our investigation. Theoretically, the only "real" unsteady simulation would be if you realize the rotation via rigid body motion or using overset.