CFD Online Logo CFD Online URL
Home > Forums > FLUENT

convergence of the solution

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

LinkBack Thread Tools Display Modes
Old   July 3, 2009, 08:33
Default convergence of the solution
Join Date: Mar 2009
Posts: 31
Rep Power: 10
amar is on a distinguished road
Sponsored Links
Dear all

I'd like to know what is the criteria to be sure that my solution is really converged.

thanks a lot
amar is offline   Reply With Quote
Sponsored Links

Old   July 3, 2009, 08:45
Super Moderator
-mAx-'s Avatar
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,232
Rep Power: 34
-mAx- will become famous soon enough
If you have a goal, then monitor it (force, pressure at inlet , massflow rate, etc..).
You achieve convergence if the monitoring doesn't fluctuate anymore with iterations
In memory of my friend Hervé: CFD engineer & freerider
-mAx- is offline   Reply With Quote

Old   July 5, 2009, 09:08
New Member
Join Date: Jul 2009
Posts: 7
Rep Power: 10
Monker1980 is on a distinguished road
Convergence criteria are very problem dependent. My usual approach is to monitor a variety of variables (e.g. velocity at several points, forces on the body, mass flow rates) - the more the better really. As -mAx- says, once the values of these have stabilised then you have a converged solution. BUT only IF your residuals have fallen by a suitable amount from their initial values (don't rely on Fluent's default 10e-3 convergence criteria). What is a suitable amount? Again, very problem dependent, but for a steady-state external aerodynamics type problem I would expect the continuity residual to drop below 10e-6 and the velocity (momentum) residuals to drop much lower than that. The Fluent user guide has some helpful guidance on this too.
Monker1980 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
Convergence of CFX field in FSI analysis nasdak CFX 2 June 29, 2009 01:17
Solution calculations and convergence in Fluent Freeman FLUENT 7 May 3, 2009 22:26
IcoFoam parallel woes msrinath80 OpenFOAM Running, Solving & CFD 9 July 22, 2007 02:58
Could anybody help me see this error and give help liugx212 OpenFOAM Running, Solving & CFD 3 January 4, 2006 19:07
General Unsteady solution convergence Freeman Main CFD Forum 0 December 7, 2005 18:08

Sponsored Links

All times are GMT -4. The time now is 05:31.