CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > FLUENT

Resolved Reynolds Stress in LES

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

Like Tree2Likes
  • 2 Post By flotus1

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   July 23, 2013, 22:40
Post Resolved Reynolds Stress in LES
  #1
New Member
 
Steve
Join Date: Feb 2013
Posts: 3
Rep Power: 13
yinyueqiang is on a distinguished road
Hi All,

I am running a case using LES on Fluent, and trying to get the Reynolds stress(<u1'u2'>) distribution on some locations of the computation domain. So after my case have been running and averaged for abundant time, I click Results->Plot->Unsteady Statistics, and then found "Resolved UV Reynolds Stress". Does anyone know how this "Resolved UV Reynolds Stress" is defined? Is it still <u1'u2'> ? By indicating "Resolved", does it mean there is another part of (unresolved) Reynolds stress not included here? Thank you very much.

-Steve

Last edited by yinyueqiang; July 23, 2013 at 22:41. Reason: missed some info
yinyueqiang is offline   Reply With Quote

Old   July 24, 2013, 04:21
Default
  #2
Super Moderator
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,382
Rep Power: 46
flotus1 has a spectacular aura aboutflotus1 has a spectacular aura about
That is the basic idea behind LES. Only the large scales are resolved while the small scales are still modeled ("eddy viscosity").
Thus "Resolved Reynolds Stress" is the best guess for the actual Reynolds Stresses. In a well-resolved LES, the resolved part should be >90% of the total Reynolds stresses.
yinyueqiang and jzc like this.
flotus1 is offline   Reply With Quote

Old   July 24, 2013, 12:16
Default
  #3
New Member
 
Steve
Join Date: Feb 2013
Posts: 3
Rep Power: 13
yinyueqiang is on a distinguished road
Quote:
Originally Posted by flotus1 View Post
That is the basic idea behind LES. Only the large scales are resolved while the small scales are still modeled ("eddy viscosity").
Thus "Resolved Reynolds Stress" is the best guess for the actual Reynolds Stresses. In a well-resolved LES, the resolved part should be >90% of the total Reynolds stresses.
Many thanks Alex.

You mentioned the "Resolved Reynolds Stress" is only one part of the Reynolds stresses(the resolved part). Do you know if there is any method with which I can get the whole Reynolds stresses(not only the resolved part, but also the modeled part)? thanks again.


Steve
yinyueqiang is offline   Reply With Quote

Old   July 24, 2013, 12:48
Default
  #4
Super Moderator
 
flotus1's Avatar
 
Alex
Join Date: Jun 2012
Location: Germany
Posts: 3,382
Rep Power: 46
flotus1 has a spectacular aura aboutflotus1 has a spectacular aura about
Apart from a DNS, I cant think of a reliable method to obtain the "exact" Reynolds stresses.
But as already mentioned, if the LES is well-resolved, the differences should be negligible.
flotus1 is offline   Reply With Quote

Reply

Tags
les, reynolds stress

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How to calculate Reynolds Stress using LES data? Jongdae Kim Main CFD Forum 7 February 13, 2020 04:09
Total Reynolds Stress and Turbulence Energy Spectrum of LES sanysaly OpenFOAM Post-Processing 4 April 29, 2017 08:40
Accessing the components of the resolved Reynolds stress tensor in a LES flotus1 FLUENT 8 January 21, 2013 04:34
Reynolds Stress Models Jade M Main CFD Forum 0 April 21, 2010 17:38
●How to get Reynolds shear stress in LES ? lcw FLUENT 0 June 13, 2006 11:04


All times are GMT -4. The time now is 05:32.