CFD Online Logo CFD Online URL
Home > Forums > Main CFD Forum

How to predict the transition line in CFD?

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

LinkBack Thread Tools Display Modes
Old   November 16, 2011, 15:49
Question How to predict the transition line in CFD?
Kisorthman Vimalakanthan
Join Date: Apr 2011
Posts: 39
Rep Power: 8
k.vimalakanthan is on a distinguished road
Hi guys,

Could anyone please tell me how to actually predict transition in a 3D CFD simulation, especially at the geometry wall?

I'm using the SST Gamma Theta transition model to conduct my simulations, where I have the parameters of turbulent kinetic energy, intermittency and ReTheta of the flow are made available. I'm not sure if they will exist at the geometry wall due to the no slip condition.

I would like to separate the region of the laminar flow and turbulent flow, i.e. some flow variable that represent only transition or laminar or turbulent.

Have seen of the use of wall shear stress (contour) to predict transition, but is there a way to draw a definite line of the flow transition?

Any help is greatly appreciated
Thanks in advance
Kisorthman Vimalakanthan
Dept. of Power and Propulsion
Cranfield University
k.vimalakanthan is offline   Reply With Quote

Old   November 16, 2011, 15:53
Senior Member
sail's Avatar
Vieri Abolaffio
Join Date: Jul 2010
Location: Always on the move.
Posts: 308
Rep Power: 10
sail is on a distinguished road
hi there. what i usually do when using this model is to take a look at the wall shear stress.

the transition should then be quite noticeable.

i don't understand exactely what your mena by drawing a definite line. do you mean by hand or in within the sw?

maybe an isocontour of the wall shear stress should do the trick, or changing the legend scale to plot only the values of the turbulent or laminar region, but i don't see any differences in comparing the plot as a whole.

but again, it might just be that i've not understood completely your issue.
sail is offline   Reply With Quote

Old   November 23, 2011, 06:00
Join Date: Nov 2009
Posts: 36
Rep Power: 10
aerospaceman is on a distinguished road
It seems you want to run your simulation in two different regimes.

What I don't understand is if you already have your solution from your turbulence model, why do you want to redefine this point? You can just plot Cp vs x.

Depending on the software (eg Star-CCM+) you can manually specify where you want transition to occur, but this is normally not "the" way to go about it.
aerospaceman is offline   Reply With Quote


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
Conversion Error nuovodna Open Source Meshers: Gmsh, Netgen, CGNS, ... 14 October 1, 2010 11:07
1.7.x Environment Variables on Linux 10.04 rasma OpenFOAM Installation 9 July 30, 2010 04:43
Problems of Duns Codes! Martin J Main CFD Forum 8 August 14, 2003 23:19
Where do we go from here? CFD in 2001 John C. Chien Main CFD Forum 36 January 24, 2001 22:10
public CFD Code development Heinz Wilkening Main CFD Forum 38 March 5, 1999 12:44

All times are GMT -4. The time now is 22:49.