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

Inlet fluctuations issue in LES

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

LinkBack Thread Tools Display Modes
Old   October 15, 2012, 12:57
Default Inlet fluctuations issue in LES
New Member
Join Date: Aug 2012
Posts: 22
Rep Power: 5
Ivan is on a distinguished road
Dear All,

I am simulating a round free jet spreading in coflow air. Since I have not the pipe inside the domain, I need to generate correlated fluctuations at inlet in a way they are not dumped immediately after the inlet. For the purpose I use an algorithm from Klein (J. of Comp. Physics 186 pp652-665). Nevertheless, I have the opposite problem:
Fluctuations increase too quickly along the centerline and, consequently, the mean velocity decrease too quickly as well. Without the correlated fluctuations, the data muches pretty well the experiments instead (apart for the first few diameters, since fluctuations would start from zero in that case).

I am using a dynamic Smagorinsky model. Does someone have any clue of the reason of this behavior? May it be due to the kind of correlations I'm giving in input (i.g. does the length of the turnover and the integral length scale associated with the fluctuations I give, have an influence? and how?). Or should I look to the way fluctuations are generated by the smagorinsky algorithm?

Hope someone can help!
Ivan 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
Mass flow inlet and pressure outlet issue nikhil FLUENT 5 December 11, 2013 13:30
groovyBC elevated inlet. pos() issue grjmell OpenFOAM 6 January 23, 2013 09:14
BoundaryCondition_Mappring inlet for LES anne OpenFOAM Running, Solving & CFD 2 April 13, 2007 09:26
LES inlet length scale f.neilson Main CFD Forum 0 January 31, 2005 14:26
Fan swirl inlet for LES Eugene Main CFD Forum 0 August 25, 2004 19:54

All times are GMT -4. The time now is 02:49.