CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > ANSYS > FLUENT

inflow BC for LES

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

LinkBack Thread Tools Search this Thread Display Modes
Old   January 12, 2005, 02:57
Default inflow BC for LES
Posts: n/a
I am using LES to simulate the boundary layer flows in a wind tunnel. The boundary layer is quite thick, about 0.6m and the turbulence intensity is about 30% near the ground and it is about 5% at the top of the boundary layer. The profile of turbulence intensity (Urms/Umean) is not uniform but it can be approximated by a polynominal function to the 4th order.

The problem I've encountered is, how to input the turbulence intensity profile into FLUENT 6.1.22 when LES is used? There is a slot for input of the turbulence intensity in the pannel of "velocity inlet" in Fluent but it can only accept a fixed value.

Could anyone tell me how to do this? Or is there any paper I can consult for using LES in Fluent?

Any reply is appreciated. Thanks.
  Reply With Quote

Old   January 12, 2005, 03:34
Default Re: inflow BC for LES
Posts: n/a
in fluent doc section "10.7.3 Boundary Conditions for the LES Model" the way they have defined fluctuations , it seems the value of intensity is constant (i am not very much sure about this). But if the value of I is constant than fluent will not allow you to read it from profile.
  Reply With Quote

Old   January 12, 2005, 04:35
Default Re: inflow BC for LES
Posts: n/a

I've also noticed that and I understand the "scale of turbulence" generated by Fluent is to randomly perturb the mean value by adding a r.m.s value times a random number of Gaussian distribution with a zero mean and standard deviation of 1. If there is no direct way to control the intensity profile in Fluent, can UDF or other methods do this job?

Has anyone used LES to simulate a similar problem by Fluent? Please advise. Many thanks.
  Reply With Quote


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
inflow turbulence using LES ? panda60 OpenFOAM 5 October 15, 2009 02:32
Turbulent Inflow Conditions ali OpenFOAM Running, Solving & CFD 2 July 9, 2009 09:55
curved inflow boundary condition Rachna Main CFD Forum 0 June 16, 2006 14:31
Prescribed inflow velocity profile - how to? Alan Main CFD Forum 10 October 28, 2005 12:14
Inflow condition for the liquid fuel pool fire Jianping Zhang Main CFD Forum 0 May 1, 2003 07:24

All times are GMT -4. The time now is 22:02.