Bounding turbulence values
 

Hi,

How to change the bounding values for the turbulence parameters such as "k" and "Omega"? My simulation crashes due to "omega" becoming very low of the order of 1e-18. How can i overcome this problem. I am using K-omega + SST model.


ThnX!!

varun

Hi Varun,
I am facing the same problem as yours. I am using the k-w SST turbulence model and during iteration, I have both bounding k and omega. The min and max values are between 1e-6 to 1e+6.
FYI, I applied boundary layers on my car (it's an external aerodynamics of car in a wind tunnel case) - about 10 layers and the y+ values are between 0 to 100 (average of about 30).

I think it is because of my y+ values but I am not really sure. If it's true, then should I increase my y+ values by making the layers nearest to wall to be thicker?
Could anyone help me on this?


Regards,
Ayu

Hi Varun,
I had a similar problem of very extreme values of k and epsilon (it was a wind simulation case). Then I tried reducing the relaxation factors for k and epsilon. I gave very low value like 0.01. Of course the simulation took a long time, but the bounding values did not go to extremes.

Try it out and let me know.

Cheers,
Balakrshnan Ramakrishnan