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-   -   Doing LES with FLUENT (http://www.cfd-online.com/Forums/fluent/27422-doing-les-fluent.html)

Andre December 16, 1999 14:24

Doing LES with FLUENT
 
Hi,

I'm currently trying to do some simulations into a conical diffuser (incompressible) and I'd like to try the LES option under FLUENT. But the thing is that I don't know how FLUENT compute in the boundary layer with LES; is it use a wall model (Deardorff, Shuman, ..) (then it's like a wall function approach) or is it solve directly near the boundary (then it's like a 2 layer approach) ? That's quiet important since in consequence I don't know how to mesh in the boundary layer

Thanks in advance,

Andre.

Sung-Eun Kim December 16, 1999 19:12

Re: Doing LES with FLUENT
 
FLUENT will essentially apply linear law (u+ = y+) to your instantaneous velocity if your mesh is fine enough. Otherwise FLUENT applies the log-law. But using fine mesh near the wall will result in high aspect ratio wall cells unless you use really small mesh size in streamwise direction. Near-wall modeling is still a research area and FLUENT adopts a simple practical approach as described above, which works reasonable well when walls play passive roles.


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