The use of DSM model in turbulent channel flow

[jushi-123]

Hello Dr. Laizet and the Incompact3d Development Team,

I have been using Incompact3d for LES of turbulent channel flow and have some doubts in the DSM model. First, in the simulation of turbulent channel flow with DSM model, the test filter should be applied only in streamwise-spanwise plane or in three directions? If the test filter is applied only in streamwise-spanwise plane, the ratio of test filter width to grid filter width should be adjusted to 4**(1/3)?
Secondly, whether the filter applied to the coefficient in procedure(attached below) have some reference?

Any advice on this would be greatly appreciated!
Thank you for your support.

Best regards,
Dong W

[slaizet]

Hi,
Do not use the DSM :-) It is slow, expensive and inaccurate. Use our ILES approach. If you really want to use it then yes you will have to do some testing on how best to do the test filter and how to chose the ratio of test filter width to grid filter. We do not use the DSM so we cannot provide advice on how to use it (it is implemented only for comparison and we only tried it for the TGV case). If you want to use an explicit SGS model, then the WALE model would be more suitable than the DSM.
Best,
Sylvain