Doubt in OpenFOAM

Tushar@cfd · June 2, 2014, 06:23

Dear Foamers,

I have a doubt in OpenFOAM:

Q) What is the advantage of using relaxation factor for both fields & equations? How accurate will be the solution?

Q) How these relaxation factors are determined (for example: p="0.3" & U="0.7")? Will it affect the solution accuracy?

mechy · June 4, 2014, 01:34

these relaxation factors stand for better convergency and do not affect the acuracy

Tushar@cfd · June 4, 2014, 01:57

Thanks for the reply,

As per algorithm, it appears only equations needs under-relaxation. I was actually confused between field & equation. Anyways, these are important for convergence.

mechy · June 4, 2014, 02:06

please take a look at UEqn and pEqn of simpleFoam solver.
for U the equation is relaxed ( UEqn().relax())
but p is relaxed explicitly ( p.relax())

June 2, 2014, 06:23	Doubt in OpenFOAM	#1
Tushar@cfd Senior Member T. Chourushi Join Date: Jul 2009 Posts: 321 Blog Entries: 1 Rep Power: 17	Dear Foamers, I have a doubt in OpenFOAM: Q) What is the advantage of using relaxation factor for both fields & equations? How accurate will be the solution? Q) How these relaxation factors are determined (for example: p="0.3" & U="0.7")? Will it affect the solution accuracy?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Frequently Asked Questions about Installing OpenFOAM	wyldckat	OpenFOAM Installation	3	November 14, 2023 11:58
OpenFOAM - Validation of Results	Ahmed	OpenFOAM Running, Solving & CFD	10	May 13, 2018 18:28
OpenFOAM Foundation Releases OpenFOAM v2.3.0	opencfd	OpenFOAM Announcements from OpenFOAM Foundation	3	December 23, 2014 03:43
OpenFOAM Foundation releases OpenFOAM 2.2.2	opencfd	OpenFOAM Announcements from ESI-OpenCFD	0	October 14, 2013 07:18
The OpenFOAM extensions project	mbeaudoin	OpenFOAM	16	October 9, 2007 09:33

June 4, 2014, 01:34		#2
mechy Senior Member Join Date: Jun 2011 Posts: 163 Rep Power: 14	these relaxation factors stand for better convergency and do not affect the acuracy

June 4, 2014, 01:57		#3
Tushar@cfd Senior Member T. Chourushi Join Date: Jul 2009 Posts: 321 Blog Entries: 1 Rep Power: 17	Thanks for the reply, As per algorithm, it appears only equations needs under-relaxation. I was actually confused between field & equation. Anyways, these are important for convergence.

June 4, 2014, 02:06		#4
mechy Senior Member Join Date: Jun 2011 Posts: 163 Rep Power: 14	please take a look at UEqn and pEqn of simpleFoam solver. for U the equation is relaxed ( UEqn().relax()) but p is relaxed explicitly ( p.relax())