[nishant_hull]

Hi Holger ..
I am a new user to Openfoam. i am also working on a cylindrical pipe flow geometry with water as fluid in icoFoam and simplefoam module. The problem consist of a circular face as a inlet and another face as a outlet. (see p and U file at the end)
My pre-compiled OpenFoam was working fine for the tutorial problems but now with my current cylinderical pipe problem, this is give some error:
error is:

#0 Foam::error::printStack(Foam: :-Ostream&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libOpenFOAM.so"
#1 Foam::sigFpe::sigFpeHandler(int) in "/home/343880/OpenFOAM/OpenFOAM- 1.4.1/lib/linuxGccDPOpt/libOpenFOAM.so"
#2 Uninterpreted: [0x110420]
#3 void Foam::fvc::surfaceIntegrate<foam::vector<double> >(Foam::Field<foam::vector<double> >&, Foam::GeometricField<foam::vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libfiniteVolume.so"
#4 Foam::tmp<foam::geometricfield<foam::vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::surfaceIntegrate<foam::vector<double> >(Foam::GeometricField<foam::vector<double>, Foam::fvsPatchField, Foam::surfaceMesh> const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libfiniteVolume.so"
#5 Foam::tmp<foam::geometricfield<foam::vector<double >, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::surfaceIntegrate<foam::vector<double> >(Foam::tmp<foam::geometricfield<foam::vector<doub le>, Foam::fvsPatchField, Foam::surfaceMesh> > const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libfiniteVolume.so"
#6 Foam::fv::gaussDivScheme<foam::tensor<double> >::fvcDiv(Foam::GeometricField<foam::tensor<double >, Foam::fvPatchField, Foam::volMesh> const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libfiniteVolume.so"
#7 Foam::tmp<foam::geometricfield<foam::innerproduct< foam::vector<double>, Foam::Tensor<double> >::type, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<foam::tensor<double> >(Foam::GeometricField<foam::tensor<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::word const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libincompressibleTurbule nceModels.so"
#8 Foam::tmp<foam::geometricfield<foam::innerproduct< foam::vector<double>, Foam::Tensor<double> >::type, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<foam::tensor<double> >(Foam::GeometricField<foam::tensor<double>, Foam::fvPatchField, Foam::volMesh> const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libincompressibleTurbule nceModels.so"
#9 Foam::tmp<foam::geometricfield<foam::innerproduct< foam::vector<double>, Foam::Tensor<double> >::type, Foam::fvPatchField, Foam::volMesh> > Foam::fvc::div<foam::tensor<double> >(Foam::tmp<foam::geometricfield<foam::tensor<doub le>, Foam::fvPatchField, Foam::volMesh> > const&) in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libincompressibleTurbule nceModels.so"
#10 Foam::turbulenceModels::kEpsilon::divR(Foam::Geome tricField<foam::vector<double> , Foam::fvPatchField, Foam::volMesh>&) const in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/lib/linuxGccDPOpt/libincompressibleTurbule nceModels.so"
#11 main in "/home/343880/OpenFOAM/OpenFOAM-1.4.1/applications/bin/linuxGccDPOpt/simpleFoam"
#12 __libc_start_main in "/lib/libc.so.6"
#13 Foam::regIOobject::readIfModified() in "/home/343880/OpenFOAM/OpenFOAM- 1.4.1/applications/bin/linuxGccDPOpt/simpleFoam"
Floating point exception





The files, i am using are listed below:

1. transportproperties:

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

transportModel Newtonian;

nu nu [0 2 -1 0 0 0 0] 0.89;

CrossPowerLawCoeffs
{
nu0 nu0 [0 2 -1 0 0 0 0] 0.89;
nuInf nuInf [0 2 -1 0 0 0 0] 0.89;
m m [0 0 1 0 0 0 0] 1;
n n [0 0 0 0 0 0 0] 1;
}

BirdCarreauCoeffs
{
nu0 nu0 [0 2 -1 0 0 0 0] 0.89;
nuInf nuInf [0 2 -1 0 0 0 0] 0.89;
k k [0 0 1 0 0 0 0] 0;
n n [0 0 0 0 0 0 0] 1;
}


2. blockMeshDict

arguments "/home/343880/OpenFOAM/343880-1.4.1/run/tutorials/icoFoam/pipeflow" off;

convertToMeters 0.01;

vertices
(
(0.3 0 0)
(0 0.3 0)
(-0.3 0 0)
(0 -0.3 0)
(1 0 0)
(0 1 0)
(-1 0 0)
(0 -1 0)
(0.3 0 10)
(0 0.3 10)
(-0.3 0 10)
(0 -0.3 10)
(1 0 10)
(0 1 10)
(-1 0 10)
(0 -1 10)
);

blocks
(
hex (0 1 2 3 8 9 10 11) (10 10 20) simpleGrading (1 1 1)
hex (0 1 5 4 8 9 13 12) (10 10 20) simpleGrading (1 1 1)
hex (1 2 6 5 9 10 14 13) (10 10 20) simpleGrading (1 1 1)
hex (2 3 7 6 10 11 15 14) (10 10 20) simpleGrading (1 1 1)
hex (3 0 4 7 11 8 12 15) (10 10 20) simpleGrading (1 1 1)


);

edges
(
arc 4 5 (0.866 0.5 0)
arc 5 6 (-0.866 0.5 0)
arc 6 7 (-0.866 -0.5 0)
arc 7 4 (0.866 -0.5 0)
arc 12 13 (0.866 0.5 40)
arc 13 14 (-0.866 0.5 40)
arc 14 15 (-0.866 -0.5 40)
arc 15 12 (0.866 -0.5 40)
);

patches
(
wall fixedWalls
(
(4 5 13 12)
(5 6 14 13)
(6 7 15 14)
(7 4 12 15)
)
patch inlet
(
(0 3 2 1)
(0 4 7 3)
(0 1 5 4)
(1 2 6 5)
(2 3 7 6)
)

patch outlet
(
(8 9 10 11)
(8 11 15 12)
(9 8 12 13)
(10 9 13 14)
(10 14 15 11)

)
);

mergePatchPairs
(
);


// ************************************************** *********************** //

3. p file



dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
inlet
{
type zeroGradient;
}

outlet
{
type fixedValue;
value uniform 0;
}

fixedWalls
{
type zeroGradient;
}

}


// ************************************************** *********************** //

4. U file



dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (0 0 10.005);
}

outlet
{
type zeroGradient;
}

fixedWalls
{
type fixedValue;
value uniform (0 0 0);
}

}


// ************************************************** *********************** //




I saw your blogs on discussion group and i was glad to know that you could be able to run the same problem succesfully. I hope you could be able to guide me in this regard.
I look forward to hearing from you soon.



Nishant

[nishant_hull]

My problem is now fixed..!! []

[danielle]

Dear Foamers,
when I use my geometry in Fluent 6.3 with one or two phases I have a realistic result. In O.Foam 1.4.1 neither with turbFoam nor with twoPhaseEulerFoam gives a good (realsitic) result. when I check my mesh, I get the following message:

Time = constant

Mesh stats
points: 314704
edges: 1088715
faces: 1277556
internal faces: 1211202
cells: 492171
boundary patches: 13
point zones: 0
face zones: 0
cell zones: 2

Number of cells of each type:
hexahedra: 257595
prisms: 0
wedges: 0
pyramids: 4884
tet wedges: 0
tetrahedra: 229692
polyhedra: 0

Checking topology...
Boundary definition OK.
Point usage OK.
Upper triangular ordering OK.
Topological cell zip-up check OK.
Face vertices OK.
Number of identical duplicate faces (baffle faces): 11380
Face-face connectivity OK.
Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
Patch Faces Points Surface
wall_cylin_int_Pied 22752 10349 multiply connected surface (shared edge)
wall_cylin_ext_G 8448 8624 ok (not multiply connected)
wall_capt_inlet_G 960 980 ok (not multiply connected)
inlet3 142 76 ok (not multiply connected)
inlet2 140 75 ok (not multiply connected)
outlet 25 33 ok (not multiply connected)
Wall_top 2653 2755 ok (not multiply connected)
inlet1 78 43 ok (not multiply connected)
wall_buttom 2669 1406 ok (not multiply connected)
wal_capt_inlet_F 873 685 ok (not multiply connected)
wall_cylin_inter 809 420 multiply connected surface (shared edge)
wall_cylin_ext_F 24925 19277 ok (not multiply connected)
wall_disc_inlet 1880 949 ok (not multiply connected)
<<Writing 10349 conflicting points to set nonManifoldPoints

Checking geometry...
Domain bounding box: (-0.139998 -0.139998 -8.61533e-16) (0.139998 0.139997 0.99)
Boundary openness (-1.08376e-17 2.8904e-17 -1.39722e-16) OK.
Max cell openness = 1.66038e-15 OK.
Max aspect ratio = 21.4331 OK.
Minumum face area = 1.22452e-07. Maximum face area = 8.99153e-05. Face area magnitudes OK.
Min volume = 2.74672e-11. Max volume = 2.55601e-07. Total volume = 0.0347228. Cell volumes OK.
Mesh non-orthogonality Max: 84.9996 average: 12.6589
*Number of severely non-orthogonal faces: 49.
Non-orthogonality check OK.
<<Writing 49 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 1.33507 OK.
Min/max edge length = 0.000218421 0.0171268 OK.
All angles in faces OK.
Face flatness (1 = flat, 0 = butterfly) : average = 1 min = 0.995346
All face flatness OK.

Mesh OK.

End


1. which value should I give to nNonOrthogonalCorrectors in fvSolution ?

2. Is my mesh the problem ?(when I use 1.4 version alot of error appear in checkMesh).

thank you for help

[edwin_gonzalez]

hi to all group,

i have one question:

what so important are the time step continuity errors in a steady state simulation?

what happen if they are big?

edwin

I have the same problem with anja I have done the steps above and I have following error

Time = 0.0001

Courant Number mean: 0 max: 9.2665e-08
DILUPBiCG: Solving for Ux, Initial residual = 0, Final residual = 0, No Iterations 0
DILUPBiCG: Solving for Uy, Initial residual = 1, Final residual = 4.2086e-16, No Iterations 1
DILUPBiCG: Solving for Uz, Initial residual = 0, Final residual = 0, No Iterations 0


Unknown symmetric matrix solver AMG

Valid symmetric matrix solvers are :

4
(
ICCG
smoothSolver
PCG
GAMG
)


file: /home/rkahraman/OpenFOAM/rkahraman-1.5/run/tutorials/project/shape/system/fvSolu tion::p at line 20.

From function lduMatrix::solver::New
in file matrices/lduMatrix/lduMatrix/lduMatrixSolver.C at line 78.

FOAM exiting

someone can help me?

Emo

hi

I am using last version of OpenFOAM and also IcoFoam but that instructions above not working in my case I have a problem with AMG solver...

Emo

[ep4]

The AMG solver does not exist, the error message says that you can to use the GAMG solver to solve symmetric matrix.
Just add the G befor AMG in the system/fvSolution file.

hi

I did add G but it is not working as well

then I had that

keyword agglomerator is undefined in dictionary "/home/rkahraman/OpenFOAM/rkahraman-1.5/run/tutorials/project/shape/system/fvSol ution::p"

file: /home/rkahraman/OpenFOAM/rkahraman-1.5/run/tutorials/project/shape/system/fvSolu tion::p

From function dictionary::lookupEntry(const word& keyword) const
in file db/dictionary/dictionary.C at line 213.

Emo

where I must add "agglomerator"

any suggestion

thanks Emo

[viraj20feb]

Originally Posted by hjasak

Yup. Put zero gradient on the pressure and the continuity error will go away. The fixed gradient b.c. gives you additional flux which is not accounted for in the continuity equation.

Hrv

Hello,

I am getting a similar error. I am trying to simulate a steady state laminar flow in 5mm diameter cylindrical pipe. I have attached my log file, p, U, fvSchemes and fvSolution files. Please help.

Regards
Viraj

[gouravjee]

can anyone tell me hot to access current and old timesteps ?

[gouravjee]

Originally Posted by viraj20feb

Hello,

I am getting a similar error. I am trying to simulate a steady state laminar flow in 5mm diameter cylindrical pipe. I have attached my log file, p, U, fvSchemes and fvSolution files. Please help.

Regards
Viraj

can anyone tell me hot to access current and old timesteps ?

[viraj20feb]

Originally Posted by gouravjee

can anyone tell me hot to access current and old timesteps ?

Hi,

OpenFOAM creates folders to write data for current and previous timesteps. You can access your data in the particular folder. Also you can use the following command to make a log file for your simulations:

command | tee log

[oshubham]

Originally Posted by nishant_hull

My problem is now fixed..!! []

Hi Nishant can you tell me how did you tackle your time step continuity error.
Thanks in advance.

[zzou1@uci.edu]

Dear all,


I am new to openfoam and I am trying to solve an asymmetric jet flow in free stream and my results are not satisfying.


smoothSolver: Solving for Ux, Initial residual = 0.000508293, Final residual = 3.21941e-06, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 0.000940431, Final residual = 4.81773e-06, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.0107984, Final residual = 7.2382e-05, No Iterations 3
GAMG: Solving for p, Initial residual = 0.00121237, Final residual = 7.15837e-05, No Iterations 2
time step continuity errors : sum local = 5.58531e-05, global = 1.58563e-05, cumulative = 0.0521039
smoothSolver: Solving for epsilon, Initial residual = 0.000275732, Final residual = 1.74389e-06, No Iterations 4
smoothSolver: Solving for k, Initial residual = 0.000345624, Final residual = 2.17518e-06, No Iterations 4



The following is my fvscheme and fvsolution


ddtSchemes
{
default steadyState;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) bounded Gauss upwind limited;
div(phi,k) bounded Gauss upwind;
div(phi,epsilon) bounded Gauss upwind;
div(phi,R) bounded Gauss upwind;
div(R) Gauss linear;
div(phi,nuTilda) bounded Gauss upwind;
div((nuEff*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear limited 1;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

fluxRequired
{
default no;
p ;
}





solvers
{
p
{
solver GAMG;
tolerance 1e-07;
relTol 0.1;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration on;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 10;
mergeLevels 1;
}

"(U|k|epsilon|R|nuTilda)"
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-07;
relTol 0.01;
}
}

SIMPLE
{
nNonOrthogonalCorrectors 0;

residualControl
{
p 1e-4;
Ux 1e-4;
Uy 1e-4;
//U
"(k|epsilon)" 1e-4;
}
}

relaxationFactors
{
fields
{
p 0.3;
}
equations
{
U 0.7;
k 0.7;
epsilon 0.7;
R 0.7;
nuTilda 0.7;
}
}



Please help! Thank you!!!

[HappyS5]

Originally Posted by hjasak

How big are they? They are related to the pressure solver tolerance and you should be able to squeeze them by converging the pressure more tightly. If this doesn't work, you've probably messed up the boundary conditions.

Hrv

I have checked my boundary conditions.

Velocity: inlet: fixedValue, uniorm (0 0 25); outlet: zeroGradient; all walls: fixedValue uniform (0 0 0);

Pressure: inlet: zeroGradient; outlet: uniform 0; all walls: zeroGradient;

My continuity errors: were x.xe+35 or more.

I tightened the relTol of pressure to 1e-06 in hopes that the errors would get under control.

The flow is very turbulent.

Any suggestions on how to get continuity errors under control?

[HappyS5]

Originally Posted by HappyS5

I have checked my boundary conditions.

Velocity: inlet: fixedValue, uniorm (0 0 25); outlet: zeroGradient; all walls: fixedValue uniform (0 0 0);

Pressure: inlet: zeroGradient; outlet: uniform 0; all walls: zeroGradient;

My continuity errors: were x.xe+35 or more.

I tightened the relTol of pressure to 1e-06 in hopes that the errors would get under control.

The flow is very turbulent.

Any suggestions on how to get continuity errors under control?

I have read that reducing the time step will reduce continuity errors. Is the latter physically accurate or is it a false fix that just makes the simulation run "look" good.

Please forgive me for the ignorant question. I am new, don't know the code, and I am trying to learn about how to increase accuracy. I changed the timeStep and my continuity dropped to the range of x.xe-07 and -x.xe-07. I also changed my fvSchemes though.

Still, the continuity errors dropped, during the previous run, when I changed the timeStep in the controlDict.

[Himanshu_Shrivastava]

Hello ,
Can anyone explain what is the difference between sum local ,global and cumulative in continuity error.

Eg.: "time step continuity errors : sum local = 0.043, global = 1.13e-007, cumulative = 1.33e-007"

and Which one we have to check for deciding convergence?

P.S.: I am coming from Fluent background where we only see one value of continuity residue.

Thanks