[shereez234]

Hey guys. I am doing a low reynolds number airfoil analysis using kkl- Omega model and I expect a laminar bubble near leading edge. Can some one suggest to me whether for this model the Yplus needs to be 1 or below or between 30 to 100?

Thanks
Shereez

[shereez234]

Is there any one who can give me some help on this? Thanks in advance guys

[Artur]

Hi,

In order to use a transition model you need to get to y+ < 1.0, actually I'd suggest more like <0.5 while keeping less than 0.25 over most of your cells if you can only afford it. I suggest having a look here for very good guidance on how to set the model up in OpenFOAM:

http://www.engmech.cz/2012/proceedin...Furst_J-FT.pdf

All the best

A

[malv83]

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.