Turbulence Model switch RKE to K-omega SST

Astan · March 16, 2019, 08:54

Hi guys, i would kindly ask some questions.

i'm dealing with a problem of external aerodynamics.

In the first try, i've used k omega sst, but it diverges because of the omega bc value.

In the second try, i've used RKE, i noticed it converges very rapidly.

I would like to understand 3 things:

1) is it normal (in general )that RKE converges faster than k-omega SST?

2) is k-omega SST stability more dependend from bc used with respect to RKE?

3) how could i switch from RKE model to K - omega SST for example after some iterations?

Thanks for the time spent to read this post.

Astan

Astan · March 29, 2019, 07:56

hi guys, could anyone help me?

mzzmrt · March 31, 2019, 04:05

I think convergence behaviour for RKE and kOmegaSST will be similar for an external aerdynamics problem.

If you can setup the case correctly according to the yPlus kOmegaSST can converge...

You can check this thread:

One more time: wall functions - SST

Astan · April 6, 2019, 03:54

thanks you for the reply mzzmrt, i found usefull that thread you suggest me!

March 16, 2019, 08:54	Turbulence Model switch RKE to K-omega SST	#1
Astan Member Andrew Join Date: Mar 2018 Posts: 82 Rep Power: 8	Hi guys, i would kindly ask some questions. i'm dealing with a problem of external aerodynamics. In the first try, i've used k omega sst, but it diverges because of the omega bc value. In the second try, i've used RKE, i noticed it converges very rapidly. I would like to understand 3 things: 1) is it normal (in general )that RKE converges faster than k-omega SST? 2) is k-omega SST stability more dependend from bc used with respect to RKE? 3) how could i switch from RKE model to K - omega SST for example after some iterations? Thanks for the time spent to read this post. Astan

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March 29, 2019, 07:56		#2
Astan Member Andrew Join Date: Mar 2018 Posts: 82 Rep Power: 8	hi guys, could anyone help me?

March 31, 2019, 04:05		#3
mzzmrt Senior Member Join Date: Mar 2014 Posts: 112 Rep Power: 12	I think convergence behaviour for RKE and kOmegaSST will be similar for an external aerdynamics problem. If you can setup the case correctly according to the yPlus kOmegaSST can converge... You can check this thread: One more time: wall functions - SST

April 6, 2019, 03:54		#4
Astan Member Andrew Join Date: Mar 2018 Posts: 82 Rep Power: 8	thanks you for the reply mzzmrt, i found usefull that thread you suggest me!