CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Running, Solving & CFD

A question about the residuals

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 13, 2008, 13:06
Default Hi to all, I have a stupid qu
  #1
matteo_gautero
Guest
 
Posts: n/a
Hi to all,
I have a stupid question about the residuals that are printed by OF during the simulation. When I used Fluent, there was a window where the residuals of the equation involved in the simulation were plotted. In OF there are two kind of residuals, "initial residual" and "final residual"... which of these is the equivalent residuals of Fluent plot?

Sorry for my stupid question, but I have this doubt...

Thanks in advance,
Matteo.
  Reply With Quote

Old   March 14, 2008, 04:54
Default i dont have any experience wit
  #2
New Member
 
Laurence Griffiths
Join Date: Mar 2009
Location: Bristol, UK
Posts: 18
Rep Power: 17
lgriffiths is on a distinguished road
i dont have any experience with fluent, and quite new to foam too - but as i understood it the 'normal' residual is the one before the iteration.

the initial represents how your actual solution is progressing... if that makes sense - your 'final' residual is probably set to some criteria in fvSolutions file.

... i hope thats right
lgriffiths is offline   Reply With Quote

Old   March 14, 2008, 06:58
Default Hi Laurence, thanks for your
  #3
matteo_gautero
Guest
 
Posts: n/a
Hi Laurence,
thanks for your response. I asked this because my friend told me that the correspondent residual of Fluent in OF is the first ("initial residual") and I'm not sure of this.

Matteo.
  Reply With Quote

Old   March 14, 2008, 10:41
Default yes, using the final resid
  #4
New Member
 
Laurence Griffiths
Join Date: Mar 2009
Location: Bristol, UK
Posts: 18
Rep Power: 17
lgriffiths is on a distinguished road
yes,

using the final residual to check the convergence of your solution wouldnt really make sense - if you check the fvSolutions file, your final residual should be converging too (or less than) the tolerances defined for the respective matrix solvers (hence wont give the standard 'convergence' curves).


the initial residual, will be your residual between your time steps - so your friend is correct if this is what fluent is plotting.
lgriffiths is offline   Reply With Quote

Reply


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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Residuals maka OpenFOAM Bugs 0 August 4, 2008 15:07
Residuals cristiano FLUENT 1 March 28, 2008 17:00
residuals Siddharth Khowala FLUENT 1 June 8, 2006 04:41
Easy question about residuals Freeman FLUENT 2 February 27, 2006 00:03
Residuals? Tom Main CFD Forum 6 November 28, 2002 05:09


All times are GMT -4. The time now is 12:51.