# Transition k-kl-omega parameters at inlet

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 May 10, 2012, 09:47 Transition k-kl-omega parameters at inlet #1 New Member   Join Date: Aug 2011 Posts: 8 Rep Power: 8 Hi! I'm testing Transition k-kl-omega turbulence model. I was told that this model is very sensitive to initial parameters at flow inlet. So at boundary conditions (in my case pressure inlet) I have to input the value of laminar kinetic energy (kl), but i can`t find any equation in user manual which will help me to estimate this value. Has anybody got information obout estimating of kl for this turbulence model?

 May 11, 2012, 02:03 #2 New Member   GavrilovIY Join Date: Sep 2011 Location: Russian Posts: 5 Rep Power: 8 Hello! I'm interested in this problem too.

 May 11, 2012, 03:14 #3 New Member   Join Date: Aug 2011 Posts: 8 Rep Power: 8 I have found some information. In Fluent additional materials it is written that this parameter should be always equal 10^-6. Is it correct?

 May 11, 2012, 03:39 #4 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,352 Blog Entries: 6 Rep Power: 45 The only parameter which is important for transition model is the turbulence intensity. 2nd less important parameter is the length scale (in some papers they give value of 0.3 chord as length scale.) but it has little effect as per recent studies(I can send you papers) Edit : instead of 0.3 chord the correct formula is 0.03 chord or 3% of chord ticsh and chengyu like this. Last edited by Far; May 11, 2012 at 05:08.

May 11, 2012, 04:58
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 The only parameter which is important for transition model is the turbulence intensity. 2nd less important parameter is the length scale (in some papers they give value of 0.3 chord as length scale.) but it has effect as per recent studies(I can send you papers)
Ok, thanks for information. Than I have another question about this model: is estimation of turbulence intensity and length scale the same as for another turbulence models?

 May 11, 2012, 05:06 #6 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,352 Blog Entries: 6 Rep Power: 45 same but for some purpose. In other models turbulence intensity has no impact (as you are solving the problem fully turbulent). Whereas in transition models increasing/decreasing the turbulence intensity change the behaviour of transition from laminar to turbulent state.

May 11, 2012, 05:24
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 Originally Posted by Far same but for some purpose. In other models turbulence intensity has no impact (as you are solving the problem fully turbulent). Whereas in transition models increasing/decreasing the turbulence intensity change the behaviour of transition from laminar to turbulent state.
Ok, thank you very much. I will try different initial turbulence intensity to see the change of transition zone behaviour.

 May 11, 2012, 05:38 #8 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,352 Blog Entries: 6 Rep Power: 45 pm your email id and I shall send you the latest papers so that you get the flavour of it.

May 11, 2012, 10:27
Where did you find the information?
#9
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Sheng
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Quote:
 Originally Posted by ticsh I have found some information. In Fluent additional materials it is written that this parameter should be always equal 10^-6. Is it correct?
Hi,
Where did you the information? I can't find much information in the help documents.

Sheng

May 11, 2012, 11:37
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 Originally Posted by micro11sl Hi, Where did you the information? I can't find much information in the help documents. Sheng
At Ansys Costumer Portal

February 21, 2014, 10:45
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Goutam Saha
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Quote:
 Originally Posted by Far pm your email id and I shall send you the latest papers so that you get the flavour of it.
Could you please email me the papers:

ranamath06@gmail.com

 February 21, 2014, 11:09 here you go :) #12 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,352 Blog Entries: 6 Rep Power: 45 Shared for every one. https://dl.dropboxusercontent.com/u/...tionpapers.zip

February 21, 2014, 12:29
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Goutam Saha
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 Originally Posted by Far Shared for every one. https://dl.dropboxusercontent.com/u/...tionpapers.zip
Sorry, this link is not working.

 February 22, 2014, 13:04 #14 Super Moderator   Sijal Join Date: Mar 2009 Location: Islamabad Posts: 4,352 Blog Entries: 6 Rep Power: 45 please check it again...

 June 17, 2016, 14:37 New model #15 New Member   Alberto Join Date: Sep 2013 Posts: 24 Rep Power: 6 After 8 years, there is a new version (or new model) of the k-kl-omega model. There are a few problems with the k-kl-omega model in the farfield. One of them is the growth of Laminar Kinetic energy when separation occurs. Lopez and Walters have a paper (have not been published yet) correcting this issue: Maurin Lopez. D. K. Walters. “A recommended correction to the k-kl-omega transition sensitive eddy-viscosity model”. Journal of Fluid Engineering. This correction has to be made to the 2008 k-kl-omega model from now on. Now, Lopez and Walters also developed a new transitional model (k-omega-v2) as an alternative to the k-kl-omega one. This new model has more capabilities (it is more reliable) than the k-kl-omega model, especially in the farfield computations. Fortunately the paper for this new model is already publish. Maurin Lopez. D. K. Walters. “Prediction of transitional and fully turbulent free shear flows using an alternative to the laminar kinetic energy approach”. Journal of Turbulence, Vol 17, Iss. 3, 2016. If you see the papers, you will immediately see how the k-kl-omega model is not good for free shear flows, and how the new model corrects all those issues. From now on, k-kl-omega users have to start using the new k-omega-v2 model. Hope this helps

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