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

LES Convergence

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   December 27, 2010, 15:57
Post LES Convergence
  #1
Member
 
SM
Join Date: Dec 2010
Posts: 97
Rep Power: 15
canopus is on a distinguished road
Hello
I am trying to do LES of a coaxial air jet with Re around 14000 issuing out into atmosphere.
The computaional domain starts from the exit plane of the jets where I put a velocity distribution & outflow is assumed 30D downstream.
The code is an incompressible LES with dynamic SGS.
I have played with different grid sizes & I am getting some nice pictures.

But how can I check if the solution is acceptable?
I do not have experimental data.

I have googled and found some bits & pieces but I am not able to put them in a shape.

Can you please elaborate how to use the pointers that I found?

1. ratio of eddy viscosity to laminar viscosity?
2. FFT of velocity data and map it to the scales?
3. Kinetic energy distribution?
4. Statistical average?

Any other pointers please let me know..

Thanks
SM
canopus is offline   Reply With Quote

Old   December 27, 2010, 17:05
Default
  #2
Senior Member
 
N/A
Join Date: Mar 2009
Posts: 189
Rep Power: 17
harishg is on a distinguished road
This test case have been commonly used in many experimental studies and you should be able to find experimental data in the literature. Another option is performing LES of some well known benchmark cases to show the robustness of code and model.

What is the purpose of this study? There are so many statistical quantities that you can present. The important thing is to present the statistics which are relevant to the goal of the study.
harishg is offline   Reply With Quote

Old   December 28, 2010, 08:09
Default
  #3
Member
 
Newton KF
Join Date: Mar 2009
Posts: 36
Rep Power: 17
NewtonKF is on a distinguished road
Look for the paper of Hussein "Velocity measurements in a high-Reynolds-number, momentum-conserving, axisymmetric, turbulent jet" there are lots of experimental data for isothermal jet analyses...

For itens 2, 3 and 4 I suggest you to read the book of Pope "Turbulent Flows"...

Good luck...
NewtonKF 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
convergence problem when use pisoFoam, LES for wind tunnel case Forrest_Lei OpenFOAM 3 July 19, 2011 07:00
Convergence of CFX field in FSI analysis nasdak CFX 2 June 29, 2009 02:17
LES convergence monitors Phil FLUENT 0 May 10, 2008 18:34
LES and DES Convergence Jim Main CFD Forum 2 September 28, 2007 16:27
LES convergence problem: Ning FLUENT 2 March 14, 2007 22:08


All times are GMT -4. The time now is 10:09.