|
[Sponsors] |
January 26, 2004, 11:19 |
Question on adjusting relaxation factor
|
#1 |
Guest
Posts: n/a
|
hi everyone, I have two questions about adjusting the relaxation factor (on a steady state problem). 1) Is it true that for a given mesh, let' say for the first few hundreds iterations or so, if using the code default relaxation, I am seeing oscilation on the residuals and they no longer reduces further, then reducing the relaxation factor will get rid of the oscilation and bring the residual lower?
2) Let say that from the very beginning (1st iteration), I have over reduced the relaxation factor, and now it takes "forever" to converge. Can I, for example after few hundreds iterations, increase the relaxation factor to speed up the convergence? But by doing so, would I also get into the above situation and have to reduce the relaxation once again another few hundreds iterations later on? Thanks in advance!! |
|
January 26, 2004, 14:15 |
Re: Question on adjusting relaxation factor
|
#2 |
Guest
Posts: n/a
|
No straightforward answer except to say "try it and see" because "it depends."
No, I'm not trying to be a smart-***, that's the straight answer. Good Luck! |
|
January 26, 2004, 14:31 |
Re: Question on adjusting relaxation factor
|
#3 |
Guest
Posts: n/a
|
Hi
Jim's right its not that straight forward. In my experience if you have to play around with the relaxation factors too much or make them very small, your convergence problems lie elsewhere i.e. poor grid quality, badly possed boundary conditions, differencing scheme issues to mention but a few. Have a play and see what happens. James |
|
January 26, 2004, 15:37 |
Re: Question on adjusting relaxation factor
|
#4 |
Guest
Posts: n/a
|
Thanks for the feedback!
|
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
How to control under relaxation factor automatically? | MASOUD | Fluent UDF and Scheme Programming | 1 | June 7, 2013 16:13 |
Relaxation factor | Benzaa | Main CFD Forum | 1 | August 18, 2009 08:27 |
Relaxation and convergence | sammi | Phoenics | 0 | March 20, 2008 04:32 |
HELP needed: Energy balance in gaseous combustion | James Willie | FLUENT | 11 | August 10, 2005 05:58 |
question | K.L.Huang | Siemens | 1 | March 29, 2000 05:57 |