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-   -   what does this mean? \nabla ^3U (https://www.cfd-online.com/Forums/main/124804-what-does-mean-nabla-3u.html)

 sharonyue October 13, 2013 20:50

what does this mean? \nabla ^3U

Thanks.

 triple_r October 16, 2013 13:37

It should mean:

Where did you see this term?

 sharonyue October 16, 2013 20:20

1 Attachment(s)
Quote:
 Originally Posted by triple_r (Post 457323) It should mean: Where did you see this term?
Thanks,

You mean its a scalar rite? Actually its a simple version of the regular one. Its an equation of a turbulence model.

"Partial-average-based equations of incompressible turbulent flow"

I attach a image. This equation is tough to handle. Right now I have no idea how to solve this equation.

 Jonas Holdeman October 17, 2013 09:15

It could also be interpreted as a tensor

 FMDenaro October 17, 2013 11:09

Quote:
 Originally Posted by sharonyue (Post 457369) Thanks, You mean its a scalar rite? Actually its a simple version of the regular one. Its an equation of a turbulence model. "Partial-average-based equations of incompressible turbulent flow" I attach a image. This equation is tough to handle. Right now I have no idea how to solve this equation.

I think is a simbolic power of the operator l.Grad therefore it must be applied n times on the function

 triple_r October 18, 2013 10:30

Ignore my first answer please, I didn't see the dot product with l. As Filippo said, it is equal to application of n times in a row, and because of the dot product, it is a scalar operator.

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