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

how to choose turbulence model?

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 20, 2015, 09:01
Default how to choose turbulence model?
  #1
rsa
New Member
 
Reza
Join Date: Jun 2012
Posts: 25
Rep Power: 12
rsa is on a distinguished road
Hi,

I am wondering if anyone knows references in which explains how to choose the proper turbulence model based on the model description. for example, I am interested to know when I should change from k-epsilon to LES or maybe for a problem I have LES is an overkill. I usually start with k-epsilon realizable but I do not know how I can know before hand which method is the most proper one based on the characteristics of my case. I appreciate if anyone can send me references if there is any since I couldnt find any myself. most of the links I find are describing the turbulence model details rather when to use a specific model.

tanx
rsa is offline   Reply With Quote

Old   September 20, 2015, 15:07
Default
  #2
Senior Member
 
Filippo Maria Denaro
Join Date: Jul 2010
Posts: 6,259
Rep Power: 67
FMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura aboutFMDenaro has a spectacular aura about
Quote:
Originally Posted by rsa View Post
Hi,

I am wondering if anyone knows references in which explains how to choose the proper turbulence model based on the model description. for example, I am interested to know when I should change from k-epsilon to LES or maybe for a problem I have LES is an overkill. I usually start with k-epsilon realizable but I do not know how I can know before hand which method is the most proper one based on the characteristics of my case. I appreciate if anyone can send me references if there is any since I couldnt find any myself. most of the links I find are describing the turbulence model details rather when to use a specific model.

tanx

the answer you are looking for depends on the flow problem and on what is the goal of the simulation...

(U)RANS -> DES-> LES -> DNS

from left to right is the formulation you can adopt and the more at left you stay, the lesser are the resolved details in the solution and greatest is the effect of the turbulence model.

You can have a look to some textbooks, for example Wilcox as well as the book of Pope
FMDenaro is online now   Reply With Quote

Old   September 21, 2015, 01:42
Default
  #3
Member
 
Jingchang.Shi
Join Date: Aug 2012
Location: Hang Zhou, China
Posts: 78
Rep Power: 12
aerosjc is on a distinguished road
I got some tips at this forum, But I forget which thread it is.
  • k-omega: region near wall
  • k-epsion: dissipation is weak
  • S-A: for jet
  • For different turbulence models, dependencies on mesh are different.
aerosjc is offline   Reply With Quote

Old   September 21, 2015, 04:13
Default
  #4
New Member
 
Surya
Join Date: Jan 2014
Posts: 20
Rep Power: 11
hariswch2 is on a distinguished road
Quote:
Originally Posted by rsa View Post
Hi,

I am wondering if anyone knows references in which explains how to choose the proper turbulence model based on the model description. for example, I am interested to know when I should change from k-epsilon to LES or maybe for a problem I have LES is an overkill. I usually start with k-epsilon realizable but I do not know how I can know before hand which method is the most proper one based on the characteristics of my case. I appreciate if anyone can send me references if there is any since I couldnt find any myself. most of the links I find are describing the turbulence model details rather when to use a specific model.

tanx
Below links may be helpful to you

http://jullio.pe.kr/fluent6.1/help/html/ug/node402.htm

http://www.innovative-cfd.com/turbulence-models.html
hariswch2 is offline   Reply With Quote

Old   September 24, 2015, 15:49
Default
  #5
Senior Member
 
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,112
Rep Power: 60
LuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura aboutLuckyTran has a spectacular aura about
It may be difficult to choose between models within a class (say k-epsilon versus k-omega) but the choice should never be difficult between a RANS model compared to LES. A better question is how much turbulence modelling do you want to do?

Quote:
Originally Posted by FMDenaro View Post
(U)RANS -> DES-> LES -> DNS

from left to right is the formulation you can adopt and the more at left you stay, the lesser are the resolved details in the solution and greatest is the effect of the turbulence model.
RANS is highly modelled turbulence and DNS is no turbulence modelling. DES & LES are intermediates.

The choice is similar to asking whether you want to invest in penny stocks or NASDAQ/DOW.
LuckyTran is offline   Reply With Quote

Reply

Tags
k-epsilon, les, turbulence

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
Use of k-epsilon and k-omega Models Jade M Main CFD Forum 40 January 27, 2023 08:18
new turbulence model in Fluent C.C FLUENT 0 August 29, 2013 11:44
What model of turbulence choose to study an external aerodynamics case raffale OpenFOAM 0 August 23, 2012 06:45
Low Reynolds k-epsilon model YJZ ANSYS 1 August 20, 2010 14:57
question about turbulence model selection and sensitivity karananand Main CFD Forum 1 February 26, 2010 05:41


All times are GMT -4. The time now is 09:08.