calculate an appropriate nutilda value
 

Hi all,
I am really sick of this problem. Can anybody tell me how to calculate an appropriate nutilda (for SpalartAllmaresDDES) value that I can assign to the internal field?



I am asking this because I found out that nutilda of 0.0 at the inlet and the internalfield remain zero even, if I have a highly fluctuating flow in the U filed.
However, if I precondition the field with a super small nutilda value of 1e-38 I end up with an appropriate nutilda field. I read sth about a floting point issue. It would be great if that could be clarified by anyone and how nutilda relates to the eddy viscosity ratio?



Best H