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

Smagorinsky Sub-Grid Turbulence Model vs. Deardorff

Register Blogs Community New Posts Updated Threads Search

Like Tree1Likes
  • 1 Post By FMDenaro

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 29, 2015, 01:14
Question Smagorinsky Sub-Grid Turbulence Model vs. Deardorff
  #1
New Member
 
Join Date: Jul 2015
Posts: 5
Rep Power: 11
oksero is on a distinguished road
I was wondering if anyone could give me some details about what the primary difference between the typical Smagorinsky SGS turbulence model and the Deardorff SGS turbulence model is. Specifically the Deardorff model outlined in Deardorff (1980) found here.

For some background information, I am a graduate student in mechanical engineering using CM1 to study some high intensity wind phenomenon (CM1 is a three-dimensional, non-hydrostatic, non-linear, time-dependent numerical model designed for idealized studies of atmospheric phenomena). I am trying to get a good understanding of the sub-grid turbulence modelling used for this code, as it is a large requirement for my master's work. I have read countless papers on this turbulence modelling, I just feel like someone who is very knowledgeable on this subject would be able to explain it in a more simple and logical way.

Here's some links to CM1, and the relevant turbulence models that it uses :

http://www2.mmm.ucar.edu/people/bryan/cm1/

http://www2.mmm.ucar.edu/people/brya..._equations.pdf

http://link.springer.com/article/10.1007%2FBF00119502

Any help would be great.
oksero is offline   Reply With Quote

Old   July 29, 2015, 04:11
Default
  #2
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,849
Rep Power: 73
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by oksero View Post
I was wondering if anyone could give me some details about what the primary difference between the typical Smagorinsky SGS turbulence model and the Deardorff SGS turbulence model is. Specifically the Deardorff model outlined in Deardorff (1980) found here.

For some background information, I am a graduate student in mechanical engineering using CM1 to study some high intensity wind phenomenon (CM1 is a three-dimensional, non-hydrostatic, non-linear, time-dependent numerical model designed for idealized studies of atmospheric phenomena). I am trying to get a good understanding of the sub-grid turbulence modelling used for this code, as it is a large requirement for my master's work. I have read countless papers on this turbulence modelling, I just feel like someone who is very knowledgeable on this subject would be able to explain it in a more simple and logical way.

Here's some links to CM1, and the relevant turbulence models that it uses :

http://www2.mmm.ucar.edu/people/bryan/cm1/

http://www2.mmm.ucar.edu/people/brya..._equations.pdf

http://link.springer.com/article/10.1007%2FBF00119502

Any help would be great.

I think that the answer is detailed in the books dedicated to LES/turbulence. I suggest a reading of specialized book if you want to have a strong background in this field

You can search for books of Sagaut, Pope, Lesieur, etc.
FMDenaro is offline   Reply With Quote

Old   July 29, 2015, 10:39
Default
  #3
New Member
 
Join Date: Jul 2015
Posts: 5
Rep Power: 11
oksero is on a distinguished road
Quote:
Originally Posted by FMDenaro View Post
I think that the answer is detailed in the books dedicated to LES/turbulence. I suggest a reading of specialized book if you want to have a strong background in this field

You can search for books of Sagaut, Pope, Lesieur, etc.
Do you, or anyone reading this, have any recommendations for books that deal specifically with these two models (Deardorff (1980) TKE SGS and Smagorinsky SGS)?
oksero is offline   Reply With Quote

Old   July 29, 2015, 11:40
Default
  #4
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,849
Rep Power: 73
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by oksero View Post
Do you, or anyone reading this, have any recommendations for books that deal specifically with these two models (Deardorff (1980) TKE SGS and Smagorinsky SGS)?

Again, I suggest reading the topic in detailed book...

Smagorinsky has the idea that the eddy viscosity ni_SGS depends on a unique characteristic lenght that is related to the minimum computational grid that describes a vortical, turbulent structure. This is justified by the assumption of homogeneity and isotropy of the motion of unresolved structure below this lenght. Smagorinsky expressses the closure in terms of the single function ni_SGS = f(v_bar;delta) that is inserted in the filtered momentum equation.

Deardoff in 1980 considered a planetary flow, if I remember with stratification effects. The key is that both a supplementary unknown and a supplementary equation (TKE) are introduced. Stratification enters in the scale lenght. A paper of Lilly on PoF also considered such issue.

In my opinion, you have two different models by a conceptual point of view.
oksero likes this.
FMDenaro is offline   Reply With Quote

Old   July 29, 2015, 11:43
Default
  #5
New Member
 
Join Date: Jul 2015
Posts: 5
Rep Power: 11
oksero is on a distinguished road
Quote:
Originally Posted by FMDenaro View Post
Again, I suggest reading the topic in detailed book...

Smagorinsky has the idea that the eddy viscosity ni_SGS depends on a unique characteristic lenght that is related to the minimum computational grid that describes a vortical, turbulent structure. This is justified by the assumption of homogeneity and isotropy of the motion of unresolved structure below this lenght. Smagorinsky expressses the closure in terms of the single function ni_SGS = f(v_bar;delta) that is inserted in the filtered momentum equation.

Deardoff in 1980 considered a planetary flow, if I remember with stratification effects. The key is that both a supplementary unknown and a supplementary equation (TKE) are introduced. Stratification enters in the scale lenght. A paper of Lilly on PoF also considered such issue.

In my opinion, you have two different models by a conceptual point of view.
Thank you. That was an excellent description of each model. I suppose I am trying to find some guidance on which specific books would go into some more detail on each model.
oksero is offline   Reply With Quote

Reply

Tags
deardorff, sgs, smagorinsky, turbulence


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Fluent :- turbulence Model prince_pahariaa FLUENT 9 May 20, 2016 04:41
Spalarat - Allmaras turbulence model saisanthoshm88 Main CFD Forum 1 June 16, 2014 17:33
Compressible turbulence model issues 351Cleveland OpenFOAM 5 October 24, 2013 16:41
Centrifugal Pump and Turbulence Model Michiel CFX 12 January 25, 2010 04:20
turbulence model equation Andy Chen FLOW-3D 4 January 1, 2010 22:45


All times are GMT -4. The time now is 16:29.