[Nek5000-users] turbChannel: Questions about targetCFL and dealiasing

[nek5000-users at lists.mcs.anl.gov]

Dear Nek users,

I have some fundamental questions in terms of CFL and dealiasing in the example of turbChannel. In the .par file, I noticed that the default setting of targetCFL is as high as 3.5, which really makes the code run very fast. But, typically, this CFL value is around 0.5 using implicit fractional time-step approach based on the FV method. Why CFL could be this high here while not compromising the stability? Is it because of the spectral element method?

And Could you also please tell me when shall I turn on or off dealiasing?

Regards,

Emily
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