Learning Forum

[can.sumeyye]

Hi. I tried to check my mesh quality for les.

I found such a document: https://www.scribd.com/document/386633967/Quick-Guide-to-Setting-Up-LES-Version-1-4-for-Lars

I applied this to my own case:

I used Cw=0.325 for wale since document says so and here is the my contours:

 

But then i asked GEMINI whether or not this is true and it said "no you should use cs=0.1 to be sure" and i did what it said even if my les model is not smagorinsky(its wale) and my mesh turn out not okey. 

Should i listen gemini and use smagorinsky and decide that my mesh is not okey for a combustion case or should i stay loyal to the aformentioned document and keep the mesh for Les (and sst-sas).

[SamW]

Hello, the 0.325 value is used in the WALE model itself, so makes the most sense for post-processing in the same context. Also, I would recommend to check and make sure you're time-averaging the field appropriately when calculating the overall percent resolved.

Finally, keep in mind that there are a lot more sources of uncertainty in turbulent combustion (mechanism, turbulent combustion closure, flame brush resolution, other physics assumptions). This resolution check can indeed give you a good estimate for how well your grid is resolving turbulence, but it's generally most important to compare your results vs. experiments or other numerical studies.