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

Fluent transient solver keeps iterating, although residual is reached on first iter

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

Reply
 
LinkBack Thread Tools Display Modes
Old   February 10, 2014, 04:24
Default Fluent transient solver keeps iterating, although residual is reached on first iter
  #1
New Member
 
Join Date: Nov 2013
Posts: 2
Rep Power: 0
r61514 is on a distinguished road
Hi everybody,

I have some difficulties understanding the convergence behavior of a transient fluent run. At each timestep, before iterations even start, I get the message that the solution is converged. Indeed, the residuals displayed after this message are smaller then the convergence criteria I set. However, the solver doesn't stop at this point but continues for another ten or so iterations. In the second iteration the residuals jump back up and are then decreased back to convergence bound (see attached file).

I don't really know what to make of this behavior. If the solution is converged on the first iteration, shouldn't the solver stop and move to the next timestep? In that case, I'd say that the timestep is too small. But why does the solver keep iterating?

I'd be happy to hear any thoughts any of you might have!
Attached Images
File Type: jpg fluent_residual.jpg (99.5 KB, 10 views)
r61514 is offline   Reply With Quote

Reply

Tags
convergence, fluent, transient

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
a problem with convergence in buoyantSimpleFoam skuznet OpenFOAM Running, Solving & CFD 5 February 19, 2014 05:30
How to write k and epsilon before the abnormal end xiuying OpenFOAM Running, Solving & CFD 8 August 27, 2013 15:33
SLTS+rhoPisoFoam: what is rDeltaT??? nileshjrane OpenFOAM Running, Solving & CFD 4 February 25, 2013 05:13
High Courant Number @ icoFoam Artex85 OpenFOAM Running, Solving & CFD 9 January 3, 2012 09:06
Forces in OF15 richard OpenFOAM Running, Solving & CFD 166 September 17, 2011 03:24


All times are GMT -4. The time now is 11:05.