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Old   July 11, 2012, 12:21
Default Filtering DNS data
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Hello!
I see in literature people filtering DNS data to compare them with LES simulations.
The filter used in most cases is Gaussian whereas if I understand correctly when LES is performed with FVM and an SGS model its more like a top hat filtering.

So does that mean Gaussian or tophat filtering on DNS data will yield same result?

In case if this concerns reacting flow (combustion) does anything change?

Thanks in advance
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Old   July 11, 2012, 15:00
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I can't provide you with a conclusive answer to this question.
But have a look at the book by Pope: turbulent flows

The filtering operations of LES and the resulting filters are discussed in detail.
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Old   July 11, 2012, 16:17
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I know the book (I think so do all the people who work with turbulence)
and have gone through the chapter on LES.
Can you point which section in particular?
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Old   July 11, 2012, 16:47
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The matter is very complex... in principle, also filtering DNS there is no necessarily link with LES solutions ...
however, if you use FVM I suggest using a top-hat to post-filter DNS. What's more, you should use a top-hat that is as similar as possible to your implicit filter, built-in by the FV methods...

Try searching in google, you will see some papers about filtering issues...
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Old   July 12, 2012, 10:49
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Thanks for your suggestion.
Any references?
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Old   July 12, 2012, 11:04
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Quote:
Originally Posted by canopus View Post
Thanks for your suggestion.
Any references?

You can find many references on the major journals such as JFM, JCP, POF, C&F, TCFD, ecc ...

also a simple google search can help:
https://www.google.it/search?q=large...C6X_4QTtwuHwBg
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