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buoyantBoussinesqSimpleFoam strange behaviour

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Old   August 6, 2012, 18:25
Default buoyantBoussinesqSimpleFoam room case strange behaviour
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Mojtaba Amiraslanpour
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Hi,
I'm trying to model a room with some inlets and outlets which there are some heat sources included inside the room. I have set boundary conditions and everything seemed working fine. But when i refined my old mesh I couldn't get any convergency.
My residuals plot is attached.

checkMesh:

Quote:
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.0.1
Exec : checkMesh
Date : Aug 07 2012
Time : 04:35:40
Host : mojtaba-HP-Pavilion-dv5-Notebook-PC
PID : 30895
Case : /home/mojtaba/OpenFOAM/mojtaba-2.0.1/run/44/ras
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
points: 26967
faces: 266293
internal faces: 243823
cells: 127529
boundary patches: 11
point zones: 0
face zones: 0
cell zones: 0

Overall number of cells of each type:
hexahedra: 0
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 127529
polyhedra: 0

Checking topology...
Boundary definition OK.
Cell to face addressing OK.
Point usage OK.
Upper triangular ordering OK.
Face vertices OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface topology
out_flow 580 374 ok (non-closed singly connected)
wall 14506 7403 ok (non-closed singly connected)
patient_back 368 215 ok (non-closed singly connected)
patient 968 515 ok (non-closed singly connected)
light 194 116 ok (non-closed singly connected)
back_light 534 286 ok (non-closed singly connected)
staff4 1268 646 ok (non-closed singly connected)
staff3 1268 646 ok (non-closed singly connected)
staff2 1268 646 ok (non-closed singly connected)
staff1 1268 646 ok (non-closed singly connected)
air-inlet 248 168 ok (non-closed singly connected)

Checking geometry...
Overall domain bounding box (-3.05 0 -2.15) (3.05 3 2.15)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (2.20841e-17 -2.0007e-17 -1.0481e-16) OK.
Max cell openness = 2.85651e-16 OK.
Max aspect ratio = 8.21547 OK.
Minumum face area = 0.00120487. Maximum face area = 0.0611442. Face area magnitudes OK.
Min volume = 1.76884e-05. Max volume = 0.00429012. Total volume = 74.3385. Cell volumes OK.
Mesh non-orthogonality Max: 69.8871 average: 20.2651
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 0.835775 OK.

Mesh OK.

End
fvSchemes:

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
default steadyState;
}

gradSchemes
{
default Gauss linear;
}

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

laplacianSchemes
{
default none;
laplacian(nuEff,U) Gauss linear corrected;
laplacian((1|A(U)),p_rgh) Gauss linear corrected;
laplacian(kappaEff,T) Gauss linear corrected;
laplacian(DkEff,k) Gauss linear corrected;
laplacian(DepsilonEff,epsilon) Gauss linear corrected;
laplacian(DREff,R) Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p_rgh ;
}


// ************************************************** *********************** //
fvSolution:

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
p_rgh
{
solver PCG;
preconditioner DIC;
tolerance 1e-08;
relTol 0.01;
}

"(U|T|k|epsilon|R)"
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-05;
relTol 0.1;
}
}

SIMPLE
{
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;

residualControl
{
p_rgh 1e-2;
U 1e-4;
T 1e-2;

// possibly check turbulence fields
"(k|epsilon|omega)" 1e-3;
}
}

relaxationFactors
{
p_rgh 0.7;
U 0.3;
T 0.5;
"(k|epsilon|R)" 0.7;
}


// ************************************************** *********************** //
controlDict:

Quote:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.0.1 |
| \\ / A nd | Web: www.OpenFOAM.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application buoyantBoussinesqSimpleFoam;

startFrom latestTime;

startTime 0;

stopAt endTime;

endTime 3000;

deltaT 1;

writeControl timeStep;

writeInterval 10;

purgeWrite 0;

writeFormat ascii;

writePrecision 6;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;


// ************************************************** *********************** //
solution crashes in Iterations between 200 to 350. log file has been attached. in Time=340 time step continuity errors starts growing up and in Time= 348 its like this:

time step continuity errors : sum local = 7.54708e+51, global = -4.0203e+37, cumulative = -4.0203e+37

What is going wrong?
regards
mojtaba ~
Attached Images
File Type: jpg buoyantBoussinesqSimpleFoam.jpg (41.4 KB, 13 views)
Attached Files
File Type: gz log.tar.gz (52.2 KB, 6 views)

Last edited by Mojtaba.a; August 6, 2012 at 20:24.
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Old   August 7, 2012, 07:08
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Mojtaba Amiraslanpour
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Does anybody have any suggestions?

Last edited by Mojtaba.a; August 7, 2012 at 10:03.
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