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

Difference between LES and k-epsilon models??

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 28, 2011, 05:36
Default Difference between LES and k-epsilon models??
  #1
New Member
 
Luc
Join Date: Dec 2009
Posts: 4
Rep Power: 16
Lucos is on a distinguished road
Hey,
does somebody could help me on that question, I don't really see what is the main difference between these two models and what are the main advantages or drawbacks of them. I've try to find the differences in many docs but this is not really explicit, and I don't really see the point.
If somebody can give me an anwser, I'll appreciate
bye
Lucos
Lucos is offline   Reply With Quote

Old   March 28, 2011, 06:22
Default Hi
  #2
Member
 
Dynampally Pavitran
Join Date: Mar 2010
Location: India
Posts: 74
Rep Power: 16
pavitran is on a distinguished road
  1. k-epsilon is a RANS model, where the governing equations are time averaged. This is called Reynolds time averaging.
  2. In LES, we filter(volume average) the equations. Therefore the filtered variables are functions of space and time.
  3. In RANS, all turbulent scales are modeled, whereas in LES the Large scales are resolved and the small isotropic subgrid scales are modeled.
  4. The Reynolds stress term in RANS and subgrid stress term in LES are defined differently.
  5. Although LES is relatively more accurate than RANS, it is computationally very expensive. As there are stringent conditions for generating the mesh.
pavitran is offline   Reply With Quote

Old   March 28, 2011, 06:30
Default
  #3
New Member
 
Luc
Join Date: Dec 2009
Posts: 4
Rep Power: 16
Lucos is on a distinguished road
thank you very much Pavitran!
Lucos is offline   Reply With Quote

Reply

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
someone to answer..Difference between LES and RANS Nik Main CFD Forum 2 September 4, 2005 12:40
LES flamelet models Simon Newbond Main CFD Forum 1 August 5, 2005 07:17
Numerical Implementation of LES Wall models dragon Main CFD Forum 2 March 14, 2005 01:53
Mixed models in LES Pradeep Main CFD Forum 4 March 28, 2003 05:56


All times are GMT -4. The time now is 17:54.