Tuesday, May 13, 2008

Enable LES (Large Eddy Simulation) in Fluent 2D

To enable Large Eddy Simulation for Fluent two dimensional models, open the Fluent main console and type the following:
(rpsetvar 'les-2d? #t)

This will enable LES in 2D models. Note that turbulence is inherently a 3D phenomenon and using LES for two dimensional flows is not recommended. However, in certain cases such as code benchmarks or debugging, it is useful to run LES in 2D. I would also speculate that LES is a valid model in axisymmetric conditions.

Cite as:
Saad, T. "Enable LES (Large Eddy Simulation) in Fluent 2D". Weblog entry from Please Make A Note. http://pleasemakeanote.blogspot.com/2008/05/enable-les-large-eddy-simulation-in.html


  1. I am unable to open LES for a 2D case using the command that you specified.
    (After giving this command when I go in the viscous model defination options I don't see the LES option should this be like this ?)
    Can you please explain a bit more.

  2. I had a typo in the command that has to be used. I just corrected that. There was a missing hyphen.


  3. sorry, I could not open LES using your command.Could you please explain it again? Is there any difference between 2D and 3D using LES?

  4. 1. open a 2D case file
    note: check Define/Models/Viscous to verify that LES is not present for a 2D problem

    2. type (rpsetvar 'les-2d? #t) and press enter
    note: you have to include the parentheses

    3. go to: Define/Models/Viscous and you'll see that the LES model has been enabled for the 2D case.

    As I mentioned previously, turbulence is a 3D phenomenon and so, by using it to model a 2D problem your results may lose some of their predictive capabilities.

    I hope this answers your questions.

  5. just to mention that make sure there is no space left in front of the common"(rpsetvar 'les-2d? #t)" it will not working.
    as i stuck on this stupid issue for 1~2 days~just to let those new comer to take note on that

  6. Exactly what I was looking for, I need to present a paper based on this information, thanks a lot, it is going to be very helpful.

  7. hi yNot, i am working on Fluent 3D LES, i am stuck in postprocessing, can you please recommend any tutorial or something?

  8. this looks fantastic and I can't wait to try it out. Also just wanted to say that I love your blog and have been reading it a lot recently!it can help tp many people to understand it!

  9. if you have opened a double precission fluent sesion, the command should be :

    (rpsetvar 'les-2ddp? #t)
    it worked for me