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

transition onset - SST:Gamma Theta Model

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 6, 2007, 03:52
Default transition onset - SST:Gamma Theta Model
  #1
Prad
Guest
 
Posts: n/a
Hi, am having problems with ascertaining my

TRANSITION ONSET CORRELATION: Option = User Defined Transition Onset Reynolds Number = 260.0*(1.0+x/(1.0[m]))

Cant seem to figure out what happens when I change values. Maybe I've overlooked some thing. I've tried variations but they're all larger by approx. factor 2 when compared with my experimental (Ca vs. Cw plots for various angles)data. What is the influence of inlet conditions (eddy viscosity etc)? Other approaches (Langtry Menter) do not bring better results. There's very little background available. Maybe someone here works with tra- onset regularly. Any suggestions are welcome. Gracias Prad
  Reply With Quote

Old   February 8, 2007, 14:34
Default Re: transition onset - SST:Gamma Theta Model
  #2
Chebeba
Guest
 
Posts: n/a
Inlet turbulence influences transition onset to a very large extent, at least for Langtry Menter.
  Reply With Quote

Old   February 20, 2007, 11:47
Default Re: transition onset - SST:Gamma Theta Model
  #3
Adam
Guest
 
Posts: n/a
Sensitivity to inlet conditions are indicitave of the gamma theta model structure in general. Mostly Tu and viscosity ratio.

What are you modelling and how, what is your grid stats, where did you get your correlation for retheta?

Adam
  Reply With Quote

Old   February 21, 2007, 07:24
Default Re: transition onset - SST:Gamma Theta Model
  #4
Prad
Guest
 
Posts: n/a
Hi Adam, have an Eppler profile, all boundaries are 4~5x distant from the foil (2cells deep), y+ around 1, have now switched all values to default values. Drag is influencing my polar which is straying from experimental values.Thanks for further info Prad
  Reply With Quote

Old   February 21, 2007, 10:32
Default Re: transition onset - SST:Gamma Theta Model
  #5
Adam
Guest
 
Posts: n/a
Prad,

Not sure what you mean. Could you please give me more information before I can help you.

Thanks

Adam
  Reply With Quote

Reply


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
Gamma Theta model and underpredicted lift Nick R CFX 29 July 22, 2011 01:03
SST Transition model in Fluent 12.0 Far FLUENT 1 November 8, 2010 02:32
anybody's done airfoil model with transition? Hao CFX 3 March 11, 2009 22:31
Re: Transition Model Michael K H Kim Main CFD Forum 1 September 23, 1999 14:30
k-omega model and unsteady transition Jens Thurso Main CFD Forum 1 May 4, 1999 10:50


All times are GMT -4. The time now is 18:38.