[niyas]

Dear Foamers,



Recently I came across two files in the '0' folder called alphaSgs and muSgs. I checked online and I couldn't get much information.



Does anybody know what is mean by alphaSgs and muSgs ?



Thanks in advance,

[Tobermory]

SGS = subgridscale, mu is the dynamic viscosity and alpha is the thermal diffusivity. So these files are the fields for the subgridscale (non-resolved) effective viscosity and thermal diffusivity in your LES simulation. If this is NOT an LES simulation, then you have a problem/intruder!

[niyas]

Hi Tobermory,



Thanks for your reply.



Yes. My simulation is LES.

Do you have/refer any material to study some basics of subgridscale ?

[Tobermory]

I would suggest starting with a simple google on "Large Eddy Simulation" ... the wikipedia article for example will walk you through the basics. Then search for some more detailed write ups, and look for academic publications of LES for a similar geometry/test case that you are trying to run. Read through a few online PhD theses, since these often lay out the fundamentals.

It's REALLY important to understand the difference between RANS and LES (resolution of scales, averaging times and sampling frequency, boundary conditions and initial conditions), if you are planning to do LES work - there are so many ways to fall down, compared to RANS modelling.

[niyas]

Hi Tobermory,


Thank you very much for your reply.



I will work on it and update here in the thread if I have any further questions.