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

not convergence in high angle of attack in low reynold number

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

Reply
 
LinkBack Thread Tools Display Modes
Old   October 1, 2009, 01:14
Default not convergence in high angle of attack in low reynold number
  #1
New Member
 
labib
Join Date: Jun 2009
Posts: 25
Rep Power: 8
nuimlabib is on a distinguished road
why at the angle of attack iof airfoil s increased in the range of 10 degrees, iteration does not converge, but at a low angle of attack 0 to 8 degrees, to achieve convergence, I use the segregated solver, implicit, and K-W turbulence models, why can not achieve convergence. where lies the fault .. I put the inlet velocity boundary conditions of 2.5m / s, and the chord length 1m. help me..
nuimlabib is offline   Reply With Quote

Old   October 2, 2009, 14:10
Default
  #2
New Member
 
Josh
Join Date: Sep 2009
Posts: 14
Rep Power: 7
jstults is on a distinguished road
Quote:
Originally Posted by nuimlabib View Post
why at the angle of attack iof airfoil s increased in the range of 10 degrees, iteration does not converge, but at a low angle of attack 0 to 8 degrees, to achieve convergence
Take a look at your residuals, you will probably notice that they are large and unsteady on the upper aft portion of your airfoil, and you'll probably have some unsteady shedding behaviour as well that will cause high residuals in the wake.

At high angles of attack, there isn't really a physically meaningful 'steady-state' for you to converge to, the physically meaningful solution is unsteady.
jstults is offline   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
Transient Angle of Attack Simulation Not Displaying in Post Josh CFX 35 August 5, 2009 09:16
low and high Reynlods numbers amar FLUENT 1 July 23, 2009 11:51
Unaligned accesses on IA64 andre OpenFOAM 5 June 23, 2008 10:37
Low Reynolds number K-Omega modeling Athar Zaidi Main CFD Forum 0 October 31, 1999 14:59
Difficulties in solving a high Reynolds number Flow? wowakai Main CFD Forum 10 December 29, 1998 14:46


All times are GMT -4. The time now is 06:30.