probleme of simpleFoam convergence

sima_op · January 23, 2014, 12:30

hallo, foamers,
- Introduce of my case:
I'm doing a simulation of incompressible, turbulent flow, two outlets with different pressure, I use inletoutlet boundary condition.For solver i use simpleFoam.

There is no problem of my mesh quality, checked by 'checkMesh'.

If i close one outlet, it will converge well.
(Here in the attachments is my 'boundary conditions' 'fvScheme' and 'fvSolution'. and my result of calculate)
Problem:
You can see that the 'Initial residual' increase after about '50' iterations. I have no idea about this..
I think it's the problem of settings in 'fvScheme', but i don't know how to deal with it, because i don't understand these schemes at all. If anyone can give me some suggestions...
Thanks very much for your help.

resultat.txt

sima_op · January 24, 2014, 03:07

is there anyone know why?

alexeym · January 24, 2014, 03:45

Hi,

As you've only provided fvSchemes and fvSolution, try using PCG instead of GAMG and PBiCG instead of smoothSolver.

Attach solution logs at least if you've got rather secret case files.

sima_op · January 24, 2014, 04:38

Quote:

Originally Posted by alexeym

Hi,

As you've only provided fvSchemes and fvSolution, try using PCG instead of GAMG and PBiCG instead of smoothSolver.

Attach solution logs at least if you've got rather secret case files.

Thanks very much for your reply, log file is this: resultat.txt . i just copy some iterations, can you open it?

alexeym · January 24, 2014, 07:30

Well, you've just shown a log with GAMG and smoothSolver. Still there are lots of possibilities of what's happening. So I can keep guessing or let it go.

1. What are your BCs for turbulence model?
2. What will happen if you remove relaxation?
3. Are you sure there is steady state in the problem?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
SimpleFoam convergence problem with really simple simulation	mayank.dce2k7	OpenFOAM Running, Solving & CFD	2	November 19, 2013 05:28
convergence of QUICK scheme - simpleFoam	Luis Batista	OpenFOAM Running, Solving & CFD	10	May 11, 2013 17:35
Convergence and steady state using simpleFoam	sfigato	OpenFOAM Running, Solving & CFD	0	February 8, 2013 04:14
Force can not converge	colopolo	CFX	13	October 4, 2011 22:03
Definition of convergence criterion in simpleFoam	titio	OpenFOAM Running, Solving & CFD	1	February 6, 2010 01:34

January 24, 2014, 03:07		#2
sima_op New Member xingyu SIMA Join Date: Sep 2013 Posts: 6 Rep Power: 12	is there anyone know why?

January 24, 2014, 03:45		#3
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Hi, As you've only provided fvSchemes and fvSolution, try using PCG instead of GAMG and PBiCG instead of smoothSolver. Attach solution logs at least if you've got rather secret case files.

January 24, 2014, 07:30		#5
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Well, you've just shown a log with GAMG and smoothSolver. Still there are lots of possibilities of what's happening. So I can keep guessing or let it go. 1. What are your BCs for turbulence model? 2. What will happen if you remove relaxation? 3. Are you sure there is steady state in the problem?