Hi all, My understanding is that in order to run a transient simulation of, say, an impeller in CFX5.6, I need to set 'Transient Rotor' and specify simulation type as Transient. However, if I set Frozen Rotor(steady state) and again set the simulation type as Transient, what is the implication of this as far as numerics or physics is concerned.

Thanks, New CFX5.6 user

I doubt the GUI will even let you do that because the frozen rotor model only makes sense in steady state calculations.

Neale

Hi Neale, Yes, I thought so too. I imagined that when I specify frozen rotor, the transient option would not be available. But it was available and I did set Frozen rotor with Transient, no error message was sent to me. The one thing I noticed was that the residuals were not being updated after every time step.

Is it correct to assume that the grids were not moving but the transient terms in the governing equations were being solved?

New User

I imagine that the transient option is still available to you as you could be investigating the effect of say a changing inflow and are not specifically interested in the effect across your rotating/stationary boundary.

However I cannot imagine that in your case a transient solution would make any difference to your result as you have included no tranisent effects in your boundary conditions/interfaces.

Cheers

Roy