treating unresolved scale
Hello, every one.
I have a question with filtering in LES. Let original flow u and filtered flow <u>. Then unresolved scale become u'=u<u> If I filter the unresolved scale, i.e., <u'>, I want to know whether this value will be 0 or not? Thank you for reading! YE. 
The answer is "no", unless you use a projective filter. Try by yourself in MATLAB with a simple 1D function (sum of sines) and different filters. The spectral cut off is the only filter which gives exactly 0.

Thanks, Sbaffini!
Quote:
Thank you for your help! 
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