code_saturne User's Forum

Dear developers,

Sorry to bother you again.

In code_saturne 7.0.4, I noted that the parameter of LES is different with other sovlers like charLES or some reference[Pope 2000 Turbulent flows] about LES. More specifically, the computation for filtered size is that,

delta = xfil *(xa*volume(iel))**xb,

where xfil defaults to 2.0, xa to 1.0, xb to 1/3, which is different with other references that use xfil to be 1.0

Second, the double filtered size of dynamic model in LES equation is that,

deltaf = xfil2*delta,

where xfil2 = 1.5 ,which is also different with other sovler that use xfil2 to be 2.0

Therefore, I want to figure out why these parameters are set like that which is different with the LES textbook and other sovler.

Best regards,
Yuxuan Chen

Hello,

Checking with colleagues, it seems this must also be adjusted based on the numerical implementation/discretization, and I remember assisting an argument between several top-level turbulence specialists regarding the a factor of 2 in the interpretation of the filter width.

There might be more details in S. Benhamadouche's Thesis (https://www.librarysearch.manchester.ac ... c&offset=0),

Best regards,

Yvan