k-omega problem

liuyuxuan · August 5, 2009, 05:39

I have question about the model K-omega , I know this model is time average. So, when I use the k-omega model, is this means that there are no different unsteady or steady?

I do not know how to use FLUENT help to solve this problem.

Thank you very much!

vishyaroon · August 5, 2009, 09:25

Not only k-w but all RANS models can be steady or unsteady. When your computation is carried out in a steady state frame work you are working with steady RANS models. In unsteady cases, the URANS kicks in and you are working with something that is closer to phase-average as compared to time average. This as I mentioned is valid for the k-w as well as the other RANS models.

liuyuxuan · August 6, 2009, 04:09

Thank you vishyaroon.

how could I know that the unsteady k-omega model is convergenced?

vishyaroon · August 6, 2009, 09:23

The unsteady k-w model is activated when you are doing an unsteady computation in the software. The convergence of the k and w equations are no different from the convergence of the other equations you are looking at (continuity, energy and momentum).

August 5, 2009, 05:39	k-omega problem	#1
liuyuxuan New Member LiuYuxuan Join Date: Jun 2009 Posts: 7 Rep Power: 16	I have question about the model K-omega , I know this model is time average. So, when I use the k-omega model, is this means that there are no different unsteady or steady? I do not know how to use FLUENT help to solve this problem. Thank you very much!

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August 5, 2009, 09:25		#2
vishyaroon Senior Member Aroon Join Date: Apr 2009 Location: Racine WI Posts: 148 Rep Power: 17	Not only k-w but all RANS models can be steady or unsteady. When your computation is carried out in a steady state frame work you are working with steady RANS models. In unsteady cases, the URANS kicks in and you are working with something that is closer to phase-average as compared to time average. This as I mentioned is valid for the k-w as well as the other RANS models.

August 6, 2009, 04:09		#3
liuyuxuan New Member LiuYuxuan Join Date: Jun 2009 Posts: 7 Rep Power: 16	Thank you vishyaroon. how could I know that the unsteady k-omega model is convergenced?

August 6, 2009, 09:23		#4
vishyaroon Senior Member Aroon Join Date: Apr 2009 Location: Racine WI Posts: 148 Rep Power: 17	The unsteady k-w model is activated when you are doing an unsteady computation in the software. The convergence of the k and w equations are no different from the convergence of the other equations you are looking at (continuity, energy and momentum).