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-   -   what's the difference between "smagorinsky" and "smagorinsky2" ? (https://www.cfd-online.com/Forums/openfoam/69632-whats-difference-between-smagorinsky-smagorinsky2.html)

panda60 October 29, 2009 05:10
what's the difference between "smagorinsky" and "smagorinsky2" ?
 
Dear Foamers,
I am a beginer of LES, I want to use the standard smagorinsky model.
In OpenFOAM, has smagorinsky and smagorinsky2 model.
what's the differences between them ? want is the 3-D filter ?

In OpenFOAM tutorials directory, only has one case using oneEaEddt, so it can't be used to modify.
If use smagorinsky model , them how many variables should be set for initial and boundary condition in 0 directory ?

Thank you very much.

StSchiff October 8, 2010 03:36
Hey Panda,
Did you ever get an answer to that question? Do you know how to run Smagorinsky2? Somehow it doesn't run with pisoFoam...
Regards
Stefanie

maysmech April 30, 2011 04:31
Hi,
I have this question too. Any idea?

maysmech April 30, 2011 05:52
Another question:
As you know Cs can be 0.1~0.2. I think default value is 0.2 for smagorinsky. Isn't it?
I want set it 0.1 to decrease diffusion in my simulation. What should be done to do that?

Regards,
Maysam

adambarfi May 9, 2014 02:28
hi everybody,

somewhere I read that Smagorinsky2 is the Smagorinsky model with 3-D filter, is it true?
in other word can I use Smagorinsky for 3D flows or I must use Smagorinsky2 instead?

can anyone explain the difference between these two models?

thanks in advance,
Mostafa

cnsidero May 9, 2014 09:30
The source code is your friend. Verbatim from their respective header files:

from $FOAM_SRC/turbulenceModels/incompressible/LES/Smagorinsky/Smagorinsky.H
Code:
B = 2/3*k*I - 2*nuSgs*dev(D)
Beff = 2/3*k*I - 2*nuEff*dev(D)

where

D = symm(grad(U));
k = (2*ck/ce)*delta^2*||D||^2
nuSgs = ck*sqrt(k)*delta
nuEff = nuSgs + nu
from $FOAM_SRC/turbulenceModels/incompressible/LES/Smagorinsky2/Smagorinsky2.H
Code:
B = 2/3*k*I - 2*nuSgs*dev(D) - 2*cD2*delta*(D.dev(D));
Beff = 2/3*k*I - 2*nuEff*dev(D) - 2*cD2*delta*(D.dev(D));

where

D = symm(grad(U));
k = cI*delta^2*||D||^2
nuSgs = ck*sqrt(k)*delta
nuEff = nuSgs + nu


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