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

Influence of turb. intensity at the inlet?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   December 21, 2005, 19:15
Default Influence of turb. intensity at the inlet?
  #1
Ianina
Guest
 
Posts: n/a
Hi,

one question about turbulence intensity:

I am modeling the flow past a bluff body (hemisphere) attached to a wall of a channel. Conditions: turbulent, subcritical. I am using k-omega SST turbulent model with appropriate grid resolution near the wall (y+ = 0.5 at max). Also second order discretization schemes are used. The body is placed approx. 6 diameters downstream from the inlet to investigate the effect of different gradients in velocity profile. Turbulence intensity is given according the recommendations of Fluent manual (in this case about 4%)

I would like to ask for the opinion on following: comparing the distributions of Cp with the wind channel experiments i get a different position of min Cp (at 80 degrees) as it was measured (at 75-78 degrees) and consequentially later separation. In this case solution converges to a steady state. I tried to set the turb. intensity to 1 % and got separation earlier but solution does not converge any more to a steady state. Is it physical behavior or the problem of the turbulence model? I noticed some messages on the problems with convergence at a low turbulence level in the forum before.

Any opinion is highly appreciated

Ianina
  Reply With Quote

Reply

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
Setting dynamic pressure as the inlet BC ruined FLUENT 1 March 26, 2008 06:30
Setting static pressure as the inlet BC ruined FLUENT 1 March 21, 2008 15:57
Low Inlet Turb. Intensity - SST model not converge Pete CFX 0 November 12, 2005 02:26
UDF problem : inlet velocity in cyl. coord. system Jongdae Kim FLUENT 0 June 15, 2004 11:21
length scales at inlet for internal flows Anne-Marie Giroux Main CFD Forum 3 July 5, 1999 21:28


All times are GMT -4. The time now is 03:19.