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calculate an appropriate nutilda value

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Old   December 7, 2017, 06:07
Default calculate an appropriate nutilda value
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hulli graemer
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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?



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eddy viscosity, nutilda, spalart allamaras


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