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

Convergence and steady state using simpleFoam

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   February 8, 2013, 04:14
Default Convergence and steady state using simpleFoam
  #1
Senior Member
 
sfigato's Avatar
 
Marco Longhitano
Join Date: Jan 2013
Location: Aachen
Posts: 103
Rep Power: 13
sfigato is on a distinguished road
Send a message via Skype™ to sfigato
Hi Foamers,

I am doing a simulation of an hydraulic orifice by using simpleFoam. I got many problems about convergence. After several trials, I got a good solution under the physical point of view.

Nevertheless, I still have some doubts regarding the convergence.
Here there are my fv Schemes and my fvSolution files:


Quote:

ddtSchemes
{
default steadyState;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss upwind;
div(phi,k) Gauss upwind;
div(phi,omega) Gauss upwind;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p;
}
Quote:
solvers
{
/* p
{
solver PCG;
preconditioner DIC;
tolerance 1e-12;
relTol 0.1;
minIter 1;
//maxIter 100;
}*/

p
{
solver GAMG;
tolerance 1e-12;
relTol 0.1;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration on;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 10;
mergeLevels 1;
}

/*U
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-12;
relTol 0.1;
minIter 1;
//maxIter 100;
}*/

U
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-12;
relTol 0.1;
nSweeps 1;
minIter 1;
//maxIter 100;
}

/*k
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-12;
relTol 0.1;
minIter 1;
//maxIter 100;
}*/

k
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-12;
relTol 0.1;
nSweeps 1;
minIter 1;
//maxIter 100;
}

/*omega
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-12;
relTol 0.1;
minIter 1;
//maxIter 100;
}*/

omega
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-12;
relTol 0.1;
nSweeps 1;
minIter 1;
//maxIter 100;
}
}

SIMPLE
{
nNonOrthogonalCorrectors 0;

}

potentialFlow
{
nNonOrthogonalCorrectors 10;
}

relaxationFactors
{
fields
{
p 0.3;
}
equations
{
U 0.7;
k 0.7;
omega 0.7;
}

cache
{
grad(U);
}

As attachments there are all the data regarding convergence!


Although all the variables seems to converge (except for Ux), some of them still oscillate. Must I worry about it??

Additionally, I forced the convergence by edit the tolerance, unless all the variables would have decreased until reach very (VERY!!) low values!

Anyone can tell me if my solution converge or not (and if does it reach a steady state)?

Moreover, what exactly means the continuity graph (plotted by using pyFoam)?

Thanks in advance
Best Regards
Marco
Attached Images
File Type: png finalResidual.png (6.8 KB, 79 views)
File Type: png initialResidual.png (5.4 KB, 63 views)
File Type: png cont.png (3.3 KB, 57 views)
File Type: png bound.png (3.1 KB, 49 views)
sfigato 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
mass flow in is not equal to mass flow out saii CFX 12 March 19, 2018 05:21
Solver for transonic flow? Martin Hegedus OpenFOAM Running, Solving & CFD 22 December 16, 2015 04:59
Time step dependence of convergence behavior of steady state simulations in CFX Chander Main CFD Forum 5 December 23, 2013 05:31
Convergence problem using simpleFoam steady state vvqf OpenFOAM Running, Solving & CFD 12 May 18, 2011 07:51
Constant velocity of the material Sas CFX 15 July 13, 2010 08:56


All times are GMT -4. The time now is 10:03.