CFD Online Logo CFD Online URL
Home > Forums > OpenFOAM Running, Solving & CFD

Understanding pimpleFoam convergence criterion

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

LinkBack Thread Tools Display Modes
Old   March 13, 2013, 19:46
Default Understanding pimpleFoam convergence criterion
Join Date: Aug 2012
Posts: 66
Blog Entries: 1
Rep Power: 7
Nucleophobe is on a distinguished road
Hi, I have a question about convergence criteria for pimpleFoam. I read other relevant threads but couldn't find a clear answer.

My understanding is that with the simpleFoam solver, it is necessary to run until the 'p' residuals drop at least three orders of magnitude (1e-3) and the 'U' (Ux, Uy, & Uz) residuals drop about four to six orders of magnitude (1e-4 - 1e-6), then stop changing.

I'm now using pimpleFoam to obtain a transient solution (different boundary conditions). My understanding is that in this case, both the 'p' and 'U' residuals must drop around one order of magnitude per time step.

My questions:
1) Should the initial residuals drop below a certain threshold before the transient solution is considered accurate? I saw in other threads that this was mentioned, but I saw no discussion on how this criterion is determined. If this is true, are pimpleFoam solutions always wrong during start-up? I don't really understand this.
2) How do you determine the criterion for how much the residuals should drop per time step?

Thank you community!
Nucleophobe 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
problem with Min/max rho tH3f0rC3 OpenFOAM 7 February 23, 2013 06:37
Force can not converge colopolo CFX 13 October 4, 2011 22:03
convergence criterion Dominique FLUENT 5 November 24, 2006 03:36
Setting convergence criterion Vidya FLUENT 5 August 6, 2006 16:46

All times are GMT -4. The time now is 15:38.