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-   -   k-kl-w turbulence model (http://www.cfd-online.com/Forums/fluent/68120-k-kl-w-turbulence-model.html)

PrandtlGlawert September 7, 2009 20:23

k-kl-w turbulence model
 
Hi everybody,

Iīve just asked some people what could they tell me about the k-kl-w turbulence model and the answer iīve got is that itīs a kind of turbulence recently released for commercial versions, and that it has been developed specifically for laminar-turbulent transition.

Could somebody tell me something more about that? It would be VERY useful for me, i can find no information on the web about it.

My other problem is that itīs too difficult for me to get a good convergence on that model, but i do have more time to face this problem.

Any website or information about the k-kl-w model?

Thank you in advance people:):):):)

denizen September 8, 2009 02:12

you can find comprehensive information in fluent users's guide and theory guide.

regards

delfel September 9, 2009 15:14

Hello,

I've never used that model, but I imagine that modeling transition to turbulence requires a pretty fine mesh. The fluent user's guide should have the info. about grid requirements.

-sean

PrandtlGlawert September 9, 2009 16:22

Thx for your replies m8s :):):) :rolleyes::rolleyes::rolleyes:

Chenel November 5, 2009 11:05

sorry for my English, i looking for information about equations of k-kl-w model. i donīt know if k-kl-omega model is the same that k-kl model. i see fluent user guide but 3 equations model not appears.
thanks you

Far September 19, 2011 18:12

actually this model is going through the development. first model used the epsilon as turbulent length scale variable. in 2nd phase; model used the omega equation but still epsilon in other two equations. last model, which fluent has I believe, uses the omega equation with omega variable in all other equation.

besides that, there are large changes in other auxiliary equations and limiters (as you there are 24 constants in this model), which are more important to the overall model capability. among them two are very much important : one controls the by pass transition and other controls the natural transition

I can send you all three papers for these three versions.

Marabelle September 20, 2013 06:50

Quote:

Originally Posted by Far (Post 324749)

I can send you all three papers for these three versions.

@ Far!
Could you also send them to me? I only found few information to the k-kl-w model and I really want to understand it...

Far September 20, 2013 11:23

email plz......

Marabelle September 24, 2013 06:54

@Far. I sent you a personal message with my emailadress. Thank you very much!

s.m December 1, 2013 15:40

Dear Far, whould you please send me the papers related to k-kl-omega?
i really need som information about it.
here you are, this my email :
saeidehmohamadi@yahoo.com

Thank you very much:o

Monstrobolaxa March 7, 2014 13:31

SO it's been a while since this topic was last discussed.

I've used the k-kl-w and compared computational with experimental surface flow vis. The results match perfectly with transition being predicted within 2% of the wing chord. But I've only be able to compare these results on a few limited cases. Drag and lift are also within 3% of experimental.

Due to issues this turbulence model I've gone back to k-w SST, but am suffering from problems as the forces are now 5%drag and 15%lift off!

With the k-kl-w I've had flow reversal being created at the outlet, which grows and grows. Checking the the turbulence intensity I've found that there is a spot near the outlet where the side wall and moving ground where turbulence is created....leading divergence sometimes or over 1000 faces having reverse flow on the outlet.

My outlet is about 7 body lengths behind the body and upstream of the problematic area turbulence intensity is close to zero.

Anyone suffering from the same? Any miracle solutions?

Far March 7, 2014 14:24

what problems you are getting with k-kl-kw model?


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