turn off wall functions in Transition SST model?
Hello,
I would like to turn off the wall functions in the new Transition SST turbulence model in FLUENT. Most of my experience has been with the SST komega model. When I turn off the wall functions, I use the command: (rpsetvar 'kwsetwallw? #t) Is there a similar command to turn off the wall functions for the transition model? I can't seem to track down the source for the command for the komega (but it works). The flow problem I am looking at is the impingement of a submerged circular jet on a normal, flat plate (jet height/nozzle diameter = 15). The fluid is water and the jet Reynolds number is roughly 40,000. Since this problem should contain both laminar and turbulent flow, I am curious how the transition model will compare with the SST komega. The main quantity of interest is the wall shear stress in the impingement region. any suggestions are welcome. Thanks, john 
Yes. Use y+ below 1 and wall function will be turned off!!!
PS. Transition model works only for Y+ < 1 
Thanks for the reply. I'm glad to hear that the wall functions turn off automatically. I was surprised when I found that FLUENT will use wall functions with the SST komega regardless of y+.

http://www.ansys.com/Products/Simula...lence+Modeling
Quote:

Hello!
I'd want to try SST Transitional model, but my system has y+ ≈ 2.5 in some zones: does this situation hardly affect the results? or can I use this model anyway? (I think that's impossible to refine more the mesh because of memory limits...) Thanks in advance! :) 
No need to refine the mesh. Just put the first node below Y+< 1. This is mandatory. There are other restrictions are also there e.g. streamwise refinement

Hi
May I know, a) For transition SST 4 equations, in what conditions we should use the "Roughness correlation" as well as " Curvature Correction"? b) Besides, how to calculate/specify for Geometry roughness height? Thank you Naima 
All times are GMT 4. The time now is 04:01. 