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

Transitional flow from turbuletn to laminar

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

Reply
 
LinkBack Thread Tools Display Modes
Old   July 11, 2002, 05:18
Default Transitional flow from turbuletn to laminar
  #1
Bo Busk Jensen
Guest
 
Posts: n/a
Hallo Everybody

I am trying to model a geoemtry where my flow starts out as a fully turbulent velocity profile and then as the geometry chnages shape the flow undergoes transition to laminar. I am trying to use a low k-e model. However, it seems to me that transition takes place way to early. Is there any explanation for this?

Regards

Bo
  Reply With Quote

Old   July 11, 2002, 08:43
Default Re: Transitional flow from turbuletn to laminar
  #2
Seb Perron
Guest
 
Posts: n/a
Yes, there is a short explanation : As far as I know, there is no tubulence model that can predict transition from laminar to turbulent or from turbulent from laminar.

In practice, when we are familiar with the problem, we fix the transition point....
  Reply With Quote

Old   July 11, 2002, 08:44
Default Re: Transitional flow from turbuletn to laminar
  #3
Bo Busk Jensen
Guest
 
Posts: n/a
Hallo Seb

Very nice of you to give me an answer. I would very much like to get a little bit more information on fixing the transition - is it possible to do in a commercial CFD code??

Regards

Bo
  Reply With Quote

Old   July 11, 2002, 09:23
Default Re: Transitional flow from turbuletn to laminar
  #4
Joern Beilke
Guest
 
Posts: n/a
http://www.cfd-online.com/Forum/star...0.cgi?read=253
  Reply With Quote

Old   July 12, 2002, 05:04
Default Re: Transitional flow from turbuletn to laminar
  #5
Helge
Guest
 
Posts: n/a
I do not know if any commercial code is offering such a model right now. But I don't think so. Anyway, a lot of work is ongoing on that topic in the research community. So a literature survey should bring up a lot of material
  Reply With Quote

Old   July 12, 2002, 07:31
Default Re: Transitional flow from turbuletn to laminar
  #6
andy
Guest
 
Posts: n/a
I cannot comment on commercial packages today but the k-e turbulence model was developed over 30 years ago within a project on laminarisation in strongly accelerated boundary layers.
  Reply With Quote

Old   July 12, 2002, 08:08
Default Re: Transitional flow from turbuletn to laminar
  #7
Seb Perron
Guest
 
Posts: n/a
It is possible to fix he transition point with some commercial codes (such as the flow solver sold by the compagny I am working for). Sorry, I don't have much information about the major software vendors (Fluent, Star-CD, ...).

I think there is much more information on fixing the transition point with the Spalart-Almaras turb than with the other well-known models. I suggest doing some research in the litterature.
  Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
laminar pipe flow with buoyantSimpleRadiationFoam and janafThermo crashes Fabian OpenFOAM 1 September 29, 2010 11:38
modelling udf-sourceterm for transitional flow matthias FLUENT 0 November 12, 2007 13:46
Laminar flow mech FLUENT 4 February 1, 2007 15:18
CFD of laminar reactive liquid flow Ingo Meisel Main CFD Forum 5 March 12, 2004 05:38
grid for laminar flow kim FLUENT 2 April 4, 2002 02:44


All times are GMT -4. The time now is 10:56.