CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM

what's the difference between "smagorinsky" and "smagorinsky2" ?

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   October 29, 2009, 06:10
Default what's the difference between "smagorinsky" and "smagorinsky2" ?
  #1
Senior Member
 
Jiang
Join Date: Oct 2009
Location: Japan
Posts: 186
Rep Power: 6
panda60 is on a distinguished road
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.
panda60 is offline   Reply With Quote

Old   October 8, 2010, 03:36
Default
  #2
New Member
 
Stefanie Schiffer
Join Date: Mar 2010
Location: Cologne, Germany
Posts: 26
Rep Power: 6
StSchiff is on a distinguished road
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
StSchiff is offline   Reply With Quote

Old   April 30, 2011, 04:31
Default
  #3
Senior Member
 
maysmech's Avatar
 
Maysam
Join Date: Jan 2010
Posts: 320
Blog Entries: 2
Rep Power: 7
maysmech is on a distinguished road
Hi,
I have this question too. Any idea?
maysmech is offline   Reply With Quote

Old   April 30, 2011, 05:52
Default
  #4
Senior Member
 
maysmech's Avatar
 
Maysam
Join Date: Jan 2010
Posts: 320
Blog Entries: 2
Rep Power: 7
maysmech is on a distinguished road
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
maysmech is offline   Reply With Quote

Old   May 9, 2014, 02:28
Default
  #5
Senior Member
 
adambarfi's Avatar
 
Mostafa Mahmoudi
Join Date: Jan 2012
Posts: 263
Rep Power: 5
adambarfi is on a distinguished road
Send a message via Yahoo to adambarfi Send a message via Skype™ to adambarfi
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
adambarfi is offline   Reply With Quote

Old   May 9, 2014, 09:30
Default
  #6
Senior Member
 
Chris Sideroff
Join Date: Mar 2009
Location: Ottawa, ON, CAN
Posts: 308
Rep Power: 11
cnsidero is on a distinguished road
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
cnsidero is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
the effect of upwind difference hades Main CFD Forum 8 March 15, 2009 00:43
Specified Blend factor =1 Vs Central Difference Kushagra CFX 4 May 2, 2008 13:14
Difference between scaled residuals and... Dieter FLUENT 0 April 28, 2006 17:52
Fininte difference and Finite element Technique Mahendra Singh Mehra FLUENT 3 December 22, 2005 23:49
someone to answer..Difference between LES and RANS Nik Main CFD Forum 2 September 4, 2005 11:40


All times are GMT -4. The time now is 04:35.