CFD Online Logo CFD Online URL
Home > Forums > SU2

How to ascertain convergence

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

LinkBack Thread Tools Display Modes
Old   June 7, 2014, 01:24
Default How to ascertain convergence
Join Date: May 2014
Posts: 52
Rep Power: 5
hedley is on a distinguished road
Sponsored Links
In laymans terms how would one check if solution is converging or has solved . Any practical example eg look at xxxx column in the history file and if it started at 11.2 in value it should reduce to yy in 5000 iterations .

Stating residuals should be 6 orders of magnitude less just confuses me .
hedley is offline   Reply With Quote
Sponsored Links

Old   June 10, 2014, 12:45
Senior Member
Heather Kline
Join Date: Jun 2013
Posts: 267
Rep Power: 7
hlk is on a distinguished road
Thank you for your question.
The residuals are printed as the log of their value. This means that for a 6 order of magnitude decrease the number printed should decrease by 6. In your example, a six order of magnitude convergence would be indicated by 11.2 - 6 = 5.2. The number of iteration it takes to converge will depend heavily on the problem, the mesh, and the CFD settings chosen. Tools like multigrid and the CFL number can accelerate convergence.
hlk is offline   Reply With Quote

Old   June 10, 2014, 12:51
Join Date: May 2014
Posts: 52
Rep Power: 5
hedley is on a distinguished road
Thank you for this - I have been watching the output and 5000 iterations on my PC take approximately 3 hours and the residuals hardly move - This is on the sample wing SU2_CFD turb_RAM6.cfg

has anyone run this on a PC so I know what to expect
hedley 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 Centurion2011 FLUENT 44 June 20, 2017 09:57
Force can not converge colopolo CFX 13 October 4, 2011 22:03
Convergence of CFX field in FSI analysis nasdak CFX 2 June 29, 2009 01:17
Problems with convergence with an easy system franzdrs Main CFD Forum 0 June 15, 2009 18:17
Defect correction and convergence ganesh Main CFD Forum 4 June 30, 2006 14:20

Sponsored Links

All times are GMT -4. The time now is 10:52.