
[Sponsors] 
January 21, 2013, 10:15 
Smagorinsky term in SGS kinetic energy equation

#1 
New Member
Ivan
Join Date: Aug 2012
Posts: 22
Rep Power: 7 
Dear all,
I want to model the equation for the SGS turbulent kinetic energy (TKE) in LES context. Without entering the details, I have two terms I am dealing with. The first is the triple correlation (a) 1/2*(  ) which I model as c*rho*delta*sqrt(k)*dk/dt, where k is the SGS TKE and c is a certain constant, and i put together with the diffusion term. All ok until here. There is, however, the term (b) where is the residual term of the momentum equation, modelled as (c) My code follows a finite volume approach. I do not know then how to calculate this term (b). For example, is there a easy way to insert this term into the diffusion term? How this term is usually modelled (ex. implicitely or explicitely)?. Is there some paper to look at? Hope someone can help! 

January 21, 2013, 12:19 

#2 
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 3,418
Rep Power: 39 
Quote:
Maybe I have not well understood your question, but for what I see the term b) is in divergence form, thus I don't see particular problems to insert it in a finite volume constest... is the additional flux ... 

January 21, 2013, 13:43 

#3  
New Member
Ivan
Join Date: Aug 2012
Posts: 22
Rep Power: 7 
Quote:
The procedure to calculate the flux requires first the calculation of (which involves also an interpolation from points at the cell center to point at boardercell surface centers) and then a second interpolation to the surface centers. When I look at the TKE for RANS, this term is never present, so I was wondering if it is usually neglected for some reason or incorporated in some other term in some way. Of course, if not, the solution will be to compute the flux! =) 

January 21, 2013, 16:22 

#4 
Senior Member
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 3,418
Rep Power: 39 
Quote:
I never worked personally on LES modelling supplied by the kinetic energy equation, I suggest to have a look at the book of Sagaut, you can find the TKE equation and have an idea of the modelling approximations 

Thread Tools  
Display Modes  


Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
error message  cuteapathy  CFX  14  March 20, 2012 07:45 
viscous term in energy equation  seb62  OpenFOAM Running, Solving & CFD  0  March 19, 2009 04:41 
what's the macro of SGS turbulent kinetic energy?  lcw  FLUENT  1  June 13, 2006 03:08 
bouyancy term in epsilon equation  Michael  Main CFD Forum  1  June 25, 1999 10:20 
Why FVM for highRe flows?  Zhong Lei  Main CFD Forum  23  May 14, 1999 13:22 