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April 11, 2015, 15:42
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simpleFoam 3D case: crashes after 7 cycles
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#1 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11  |
Hi,
I am beginner in the field of CFD and OpenFOAM. I need some help or advice with my case. Basically I have used the PitzDaily default case of OpenFOAM tutorials but with a new 3D geometry instead of 2D and new boundary values of pressure and velocity. These are the values of p, U, k and epsilon: Code:
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
walls
{
type zeroGradient;
}
inlet
{
type fixedValue;
value uniform 200;
}
outlet
{
type fixedValue;
value uniform 0;
}
}
Code:
dimensions [0 1 -1 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
walls
{
type fixedValue;
value uniform (0 0 0);
}
inlet
{
type fixedValue;
value uniform (0 0 0);
}
outlet
{
type zeroGradient;
}
}
Code:
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0.375;
boundaryField
{
walls
{
type kqRWallFunction;
value uniform 0.375;
}
inlet
{
type fixedValue;
value uniform 0.375;
}
outlet
{
type zeroGradient;
}
}
Code:
dimensions [0 2 -3 0 0 0 0];
internalField uniform 14.855;
boundaryField
{
walls
{
type epsilonWallFunction;
value uniform 14.855;
}
inlet
{
type fixedValue;
value uniform 14.855;
}
outlet
{
type zeroGradient;
}
}
Code:
#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #2 in "/lib/x86_64-linux-gnu/libc.so.6" #3 Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #4 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMatrix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #5 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #6 Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #7 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/simpleFoam" #8 in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/simpleFoam" #9 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #10 in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/simpleFoam" by the by I would like upload a jpg file of residual values from my desktop but I don't know how do it. |
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April 11, 2015, 18:15
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#2 | |
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Senior Member
Troy Snyder
Join Date: Jul 2009
Location: Akron, OH
Posts: 220
Rep Power: 19 |
Quote:
either divergence or there is an error writing and output file. Based on what you posted it appears that the latter is more likely. Also, please post your solver settings files if they differ from the pitzDaily tutorial. |
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April 12, 2015, 07:06
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#3 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Here is the output log file:
Code:
alvaro@AlvaroPC:~/OpenFOAM/run/pitzDaily$ simpleFoam
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.3.0-f5222ca19ce6
Exec : simpleFoam
Date : Apr 12 2015
Time : 11:44:53
Host : "AlvaroPC"
PID : 2859
Case : /home/alvaro/OpenFOAM/run/pitzDaily
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 mesh for time = 0
Reading field p
Reading field U
Reading/calculating face flux field phi
Selecting incompressible transport model Newtonian
Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
sigmaEps 1.3;
}
No finite volume options present
SIMPLE: convergence criteria
field p tolerance 0.01
field U tolerance 0.001
field "(k|epsilon|omega)" tolerance 0.001
Starting time loop
streamLine streamLines:
automatic track length specified through number of sub cycles : 5
Time = 1
smoothSolver: Solving for Ux, Initial residual = 0, Final residual = 0, No Iterations 0
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.0384349, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0, Final residual = 0, No Iterations 0
GAMG: Solving for p, Initial residual = 1, Final residual = 0.095593, No Iterations 1
time step continuity errors : sum local = 52.102, global = -0.56931, cumulative = -0.56931
smoothSolver: Solving for epsilon, Initial residual = 0.988297, Final residual = 0.000247036, No Iterations 1
bounding epsilon, min: -3.70276 max: 188967 average: 41.0059
smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.0800895, No Iterations 1
ExecutionTime = 0.32 s ClockTime = 0 s
Time = 2
smoothSolver: Solving for Ux, Initial residual = 0.645571, Final residual = 0.0636477, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 0.443996, Final residual = 0.00986204, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.691369, Final residual = 0.0653874, No Iterations 1
GAMG: Solving for p, Initial residual = 0.999027, Final residual = 0.0763541, No Iterations 4
time step continuity errors : sum local = 31.7509, global = 1.89734, cumulative = 1.32803
smoothSolver: Solving for epsilon, Initial residual = 0.695385, Final residual = 2.08712e-05, No Iterations 1
smoothSolver: Solving for k, Initial residual = 0.919585, Final residual = 0.0823362, No Iterations 2
ExecutionTime = 0.45 s ClockTime = 0 s
Time = 3
smoothSolver: Solving for Ux, Initial residual = 0.440654, Final residual = 0.0427516, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 0.560425, Final residual = 0.0419665, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.410988, Final residual = 0.0349522, No Iterations 1
GAMG: Solving for p, Initial residual = 0.642045, Final residual = 0.063517, No Iterations 2
time step continuity errors : sum local = 38.5966, global = -9.32056, cumulative = -7.99253
smoothSolver: Solving for epsilon, Initial residual = 0.224899, Final residual = 3.99216e-06, No Iterations 1
bounding epsilon, min: -13464.6 max: 7.90228e+06 average: 9149.1
smoothSolver: Solving for k, Initial residual = 0.474471, Final residual = 0.045027, No Iterations 2
ExecutionTime = 0.57 s ClockTime = 0 s
Time = 4
smoothSolver: Solving for Ux, Initial residual = 0.773657, Final residual = 0.050837, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.600411, Final residual = 0.0464153, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.733712, Final residual = 0.0562857, No Iterations 2
GAMG: Solving for p, Initial residual = 0.840831, Final residual = 0.0582094, No Iterations 1
time step continuity errors : sum local = 321.621, global = 81.3235, cumulative = 73.3309
smoothSolver: Solving for epsilon, Initial residual = 0.740998, Final residual = 9.77163e-05, No Iterations 1
bounding epsilon, min: -984.549 max: 8.36834e+08 average: 362259
smoothSolver: Solving for k, Initial residual = 0.949549, Final residual = 0.0942416, No Iterations 2
ExecutionTime = 0.69 s ClockTime = 1 s
Time = 5
smoothSolver: Solving for Ux, Initial residual = 0.732108, Final residual = 0.0686708, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 0.476365, Final residual = 0.0449628, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.446049, Final residual = 0.0407226, No Iterations 1
GAMG: Solving for p, Initial residual = 0.840493, Final residual = 0.0792588, No Iterations 1
time step continuity errors : sum local = 234.221, global = 66.9484, cumulative = 140.279
smoothSolver: Solving for epsilon, Initial residual = 0.228923, Final residual = 1.06908e-06, No Iterations 1
bounding epsilon, min: -3.43861e+07 max: 6.90822e+10 average: 4.3941e+07
smoothSolver: Solving for k, Initial residual = 0.452072, Final residual = 0.0196315, No Iterations 2
bounding k, min: -485.765 max: 3.29082e+06 average: 8562.43
ExecutionTime = 0.81 s ClockTime = 1 s
Time = 6
smoothSolver: Solving for Ux, Initial residual = 0.278225, Final residual = 0.0234514, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 0.240453, Final residual = 0.0144066, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.359935, Final residual = 0.0329614, No Iterations 1
GAMG: Solving for p, Initial residual = 0.916368, Final residual = 0.0709018, No Iterations 1
time step continuity errors : sum local = 6564.03, global = 184.483, cumulative = 324.762
smoothSolver: Solving for epsilon, Initial residual = 0.013258, Final residual = 0.000666225, No Iterations 1
bounding epsilon, min: -2.72697e+08 max: 1.56504e+13 average: 4.78779e+09
smoothSolver: Solving for k, Initial residual = 0.4201, Final residual = 0.0274674, No Iterations 1
bounding k, min: -40309.9 max: 1.33333e+09 average: 716884
ExecutionTime = 0.93 s ClockTime = 1 s
Time = 7
smoothSolver: Solving for Ux, Initial residual = 0.0337342, Final residual = 0.00201148, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 0.0468805, Final residual = 0.00289706, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.0158243, Final residual = 0.000456582, No Iterations 1
GAMG: Solving for p, Initial residual = 0.110785, Final residual = 0.00775269, No Iterations 2
time step continuity errors : sum local = 2.54362e+14, global = 4.21581e+11, cumulative = 4.21581e+11
smoothSolver: Solving for epsilon, Initial residual = 1, Final residual = 0.0349246, No Iterations 3
smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.0851641, No Iterations 1
ExecutionTime = 1.05 s ClockTime = 1 s
Time = 8
smoothSolver: Solving for Ux, Initial residual = 0.515451, Final residual = 0.0207056, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.722785, Final residual = 0.0488147, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.818181, Final residual = 0.0520304, No Iterations 1
GAMG: Solving for p, Initial residual = 0.999684, Final residual = 0.0983319, No Iterations 5
time step continuity errors : sum local = 2.51385e+14, global = -2.99544e+12, cumulative = -2.57385e+12
smoothSolver: Solving for epsilon, Initial residual = 0.0130558, Final residual = 8.86302e-16, No Iterations 1
bounding epsilon, min: -1.21842e+35 max: 4.92931e+40 average: 8.18944e+36
smoothSolver: Solving for k, Initial residual = 0.5328, Final residual = 0.0426716, No Iterations 1
bounding k, min: -4.2741e+20 max: 5.74832e+36 average: 1.05138e+33
ExecutionTime = 1.2 s ClockTime = 1 s
Time = 9
smoothSolver: Solving for Ux, Initial residual = 0.0524346, Final residual = 0.00248475, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 0.22741, Final residual = 0.0195766, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.010153, Final residual = 0.000734547, No Iterations 1
GAMG: Solving for p, Initial residual = 0.00514794, Final residual = 0.000331134, No Iterations 2
time step continuity errors : sum local = 3.5522e+33, global = -1.27833e+31, cumulative = -1.27833e+31
smoothSolver: Solving for epsilon, Initial residual = 1, Final residual = 0.0524548, No Iterations 29
smoothSolver: Solving for k, Initial residual = 3.38676e-07, Final residual = 3.38676e-07, No Iterations 0
ExecutionTime = 1.35 s ClockTime = 1 s
Time = 10
smoothSolver: Solving for Ux, Initial residual = 0.646186, Final residual = 0.0522116, No Iterations 40
smoothSolver: Solving for Uy, Initial residual = 0.56795, Final residual = 0.0301241, No Iterations 41
smoothSolver: Solving for Uz, Initial residual = 0.529712, Final residual = 0.0287035, No Iterations 38
#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib/x86_64-linux-gnu/libc.so.6"
#3 Foam::GAMGSolver::scale(Foam::Field<double>&, Foam::Field<double>&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#4 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMatrix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#5 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#6 Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#7 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/simpleFoam"
#8
in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/simpleFoam"
#9 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#10
in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/simpleFoam"
Floating point exception (core dumped)
alvaro@AlvaroPC:~/OpenFOAM/run/pitzDaily$
And when you say solver settings files you mean ControlDict file, isn't it? Here is, but I didn't modified anything Code:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
application simpleFoam;
startFrom latestTime;
startTime 0;
stopAt endTime;
endTime 1000;
deltaT 1;
writeControl timeStep;
writeInterval 50;
purgeWrite 0;
writeFormat ascii;
writePrecision 6;
writeCompression off;
timeFormat general;
timePrecision 6;
runTimeModifiable true;
functions
{
streamLines
{
type streamLine;
// Where to load it from (if not already in solver)
functionObjectLibs ("libfieldFunctionObjects.so");
// Output every
outputControl outputTime;
// outputInterval 10;
setFormat vtk; //gnuplot;//xmgr;//raw;//jplot;//csv;//ensight;
// Velocity field to use for tracking.
UName U;
// Tracked forwards (+U) or backwards (-U)
trackForward true;
// Names of fields to sample. Should contain above velocity field!
fields (p k U);
// Steps particles can travel before being removed
lifeTime 10000;
// Number of steps per cell (estimate). Set to 1 to disable subcycling.
nSubCycle 5;
// Cloud name to use
cloudName particleTracks;
// Seeding method. See the sampleSets in sampleDict.
seedSampleSet uniform; //cloud;//triSurfaceMeshPointSet;
uniformCoeffs
{
type uniform;
axis x; //distance;
start (-0.0205 0.001 0.00001);
end (-0.0205 0.0251 0.00001);
nPoints 10;
}
}
}
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April 12, 2015, 14:10
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#4 |
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Senior Member
Troy Snyder
Join Date: Jul 2009
Location: Akron, OH
Posts: 220
Rep Power: 19 |
Your solution is diverging.
I would suggest running checkMesh to look for mesh issues. Also, I don't believe you can specify static pressure on both the inlet and the outlet. I would change the inlet to total pressure. |
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April 12, 2015, 15:41
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#5 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Referred to the mesh, not seen nothing unusual, except some non-orthogonal faces:
Code:
alvaro@AlvaroPC:~/OpenFOAM/run/pitzDaily2$ checkMesh
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 2.3.0-f5222ca19ce6
Exec : checkMesh
Date : Apr 12 2015
Time : 20:11:08
Host : "AlvaroPC"
PID : 3402
Case : /home/alvaro/OpenFOAM/run/pitzDaily2
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: 5865
faces: 47633
internal faces: 39075
cells: 21677
faces per cell: 4
boundary patches: 3
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: 21677
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
walls 8313 4219 ok (non-closed singly connected)
inlet 84 84 ok (non-closed singly connected)
outlet 161 101 ok (non-closed singly connected)
Checking geometry...
Overall domain bounding box (-1.66857 -0.201602 -1.67331) (2.51658 2.87607 1.67331)
Mesh (non-empty, non-wedge) directions (1 1 1)
Mesh (non-empty) directions (1 1 1)
Boundary openness (-1.95172e-16 1.45104e-16 -1.42852e-16) OK.
Max cell openness = 1.73452e-15 OK.
Max aspect ratio = 348.834 OK.
Minimum face area = 2.90131e-08. Maximum face area = 0.0227372. Face area magnitudes OK.
Min volume = 2.83827e-11. Max volume = 0.00110686. Total volume = 2.07994. Cell volumes OK.
Mesh non-orthogonality Max: 89.4051 average: 22.6028
*Number of severely non-orthogonal (> 70 degrees) faces: 57.
Non-orthogonality check OK.
<<Writing 57 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 1.82439 OK.
Coupled point location match (average 0) OK.
Mesh OK.
End
The case that I am trying to solver is a simulation of a 3D nozzle that inject diesel fuel to cylinder. The velocity is unknown, but at the entry and exit is depreciated. All that is known is the inlet and outlet pressure. The real values are 350 bar at inlet and 1 bar at outlet. How would you set the BC's for this case? Thanks. |
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April 12, 2015, 17:34
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#6 |
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Senior Member
Troy Snyder
Join Date: Jul 2009
Location: Akron, OH
Posts: 220
Rep Power: 19 |
Here is an example for setting a totalPressure boundary (in p file):
Code:
injInlet
{
type totalPressure;
U U;
gamma 1.0;
p0 uniform 111.111;
}
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April 13, 2015, 08:02
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#7 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Hi,
I tried everything you advised me, but the problem still appearing. Even so, thank you for answers and advice me. Now I am going to try make a new mesh completly structured, without non-orthogonal faces. I'll let you know if it works. Regards. |
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May 29, 2015, 09:53
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#8 | |
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Senior Member
Join Date: Mar 2015
Posts: 250
Rep Power: 12 |
Quote:
did you try with a new mesh? Did it work? Best regards, Kate |
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May 30, 2015, 06:52
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#9 | |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Quote:
I tried it with a new mesh better quality, but still doesn't work.. and I don't know why  Now I'm working with cavitatingFoam tutorial "throttle" and the same mesh and the same condition. For now the results look good for a pressure driven flow and the cavitation phenomena. Regards |
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May 30, 2015, 07:06
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#10 | |
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Senior Member
Join Date: Mar 2015
Posts: 250
Rep Power: 12 |
Quote:
did your new mesh pass all the tests from checkMesh? Another topic, I am not familiar with your type of BCs (pressure assigned at inlet AND outlet). I would look at this again. Also, I would recommend intitializing your case with turbulence switched off. Regarding your work with the "throttle" settings. You said it looks good. Congratulations! Can you give us a bit more information on this? Does it converge, is your problem solved then? Best regards, Kate P.S.: When tas38 asked about the solver settings, I think he meant the fvSolution file in the system directory. |
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June 2, 2015, 06:03
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#11 | |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Quote:
Sorry for my late reply. Yes, the new mesh pass checkMesh without problem (it's a very simple geometry of a nozzle made with blockMesh) Regarding the pressure and velocity condition: 0/p Code:
dimensions [1 -1 -2 0 0];
internalField uniform 1e5;
boundaryField
{
frontback
{
type empty;
}
inlet
{
type totalPressure;
U U;
phi phiv;
rho rho;
psi none;
gamma 1;
p0 uniform 150e5;
}
outlet
{
type fixedValue;
value uniform 1e5;
}
nozzleWall
{
type zeroGradient;
}
fixedWall
{
type zeroGradient;
}
}
Code:
{
frontback
{
type empty;
}
inlet
{
type pressureInletOutletVelocity;
value uniform (0 0 0);
}
outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value uniform (0 0 0);
}
nozzleWall
{
type fixedValue;
value uniform (0 0 0);
}
fixedWall
{
type fixedValue;
value uniform (0 0 0);
}
}
About the cavitating problem, I still have problem with convergence. The case crash a few minutes to start. The residuals look fine, the only strange thing I see is highlighted in black below. Code:
DILUPBiCG: Solving for rho, Initial residual = 3.65416e-05, Final residual = 4.73255e-11, No Iterations 1 max-min rho: 72391.2 -6.84908 max-min gamma: 1 0 DILUPBiCG: Solving for Ux, Initial residual = 0.00712085, Final residual = 1.85145e-11, No Iterations 2 DILUPBiCG: Solving for Uy, Initial residual = 0.00714144, Final residual = 1.855e-11, No Iterations 2 max(U) 1.53422e+65 GAMG: Solving for p, Initial residual = 1.99619e-05, Final residual = 3.99114e-18, No Iterations 1 Predicted p max-min : 4.9197e+10 -9.75485e+126 max-min gamma: 1 0 Phase-change corrected p max-min : 4.9197e+10 -9.75485e+126 max(U) 1.53422e+65 GAMG: Solving for p, Initial residual = 5.07469e-05, Final residual = 5.54335e-18, No Iterations 1 Predicted p max-min : 4.9197e+10 -9.75478e+126 max-min gamma: 1 0 Phase-change corrected p max-min : 4.9197e+10 -9.75478e+126 max(U) 1.53422e+65 DILUPBiCG: Solving for omega, Initial residual = 0.0591393, Final residual = 2.52565e-12, No Iterations 2 #0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #2 in "/lib/x86_64-linux-gnu/libc.so.6" #3 Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so" #4 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libfiniteVolume.so" #5 Foam::fvMatrix<double>::solve() in "/opt/openfoam211/platforms/linux64GccDPOpt/bin/cavitatingFoam" #6 Foam::incompressible::RASModels::kOmegaSST::correct() in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libincompressibleRASModels.so" #7 in "/opt/openfoam211/platforms/linux64GccDPOpt/bin/cavitatingFoam" #8 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6" #9 in "/opt/openfoam211/platforms/linux64GccDPOpt/bin/cavitatingFoam" Floating point exception (core dumped) I show the fvSolution settings if the problem was there: Code:
solvers
{
rho
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-08;
relTol 0.1;
}
rhoFinal
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-08;
relTol 0;
}
p
{
solver GAMG;
tolerance 0;
relTol 0.1;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration true;
nCellsInCoarsestLevel 10;
agglomerator faceAreaPair;
mergeLevels 1;
}
pFinal
{
$p;
tolerance 1e-08;
relTol 0;
}
"(U|k|omega)"
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-08;
relTol 0.1;
}
"(U|k|omega)Final"
{
solver PBiCG;
preconditioner DILU;
tolerance 1e-08;
relTol 0;
}
}
PIMPLE
{
nCorrectors 3;
nNonOrthogonalCorrectors 0;
}
Thanks and regards, Alvaro. |
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June 3, 2015, 06:18
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#12 |
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New Member
Al_th
Join Date: Apr 2015
Posts: 19
Rep Power: 11 |
Hi alvariten,
I notice something strange about your boundary condition. Even before being interested in the mesh, or the laminar/turbulent scheme. You impose a pressure at the inlet, but you are saying that the velocity is fixed at (0 0 0). But isn't your goal to let fluid go through the inlet ? If so, the velocity cannot be an uniform fixed value (0 0 0) and I would recommand you to change the U field for the inlet to type zeroGradient; |
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June 3, 2015, 20:43
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#13 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Hi Al_th,
I'm still learning in field of OpenFoam so I'm grateful that you advice me. What you propose makes sense. I have tried with zeroGradient at inlet and outlet but the error still appears. Yes, my goal is impose varying pressure values over time (with uniformTotalPressrue) at inlet and fixed values at outlet with the purpose to get the mass flow through the output. The velocity is unknown so the best option is to set type zeroGradient. I have no idea where is the mistake but I am struck by the warning message "FOAM Warning : From function Time:  perator++()". This is related to the Co number and it means the time precision is increase while deltaT become too small, isn't it? Could be this the reason of the problem?Code:
GAMG: Solving for p, Initial residual = 0.000137488, Final residual = 4.00266e-17, No Iterations 1
Predicted p max-min : 2.17415e+09 -704709
max-min gamma: 1 0
Phase-change corrected p max-min : 2.17415e+09 29.1545
max(U) 1.17523e+106
GAMG: Solving for p, Initial residual = 0.000160614, Final residual = 4.01508e-17, No Iterations 1
Predicted p max-min : 2.17415e+09 -773613
max-min gamma: 1 0
Phase-change corrected p max-min : 2.17415e+09 29.1545
max(U) 1.17523e+106
GAMG: Solving for p, Initial residual = 0.000135725, Final residual = 4.05313e-17, No Iterations 1
Predicted p max-min : 2.17415e+09 -878458
max-min gamma: 1 0
Phase-change corrected p max-min : 2.17415e+09 29.1545
max(U) 1.17523e+106
ExecutionTime = 372.39 s ClockTime = 446 s
phiv Courant Number mean: 6.053e-06 max: 0.550988 acoustic max: 3.23685e-103
deltaT = 1.86875e-112
--> FOAM Warning :
From function Time::operator++()
in file db/Time/Time.C at line 1010
Increased the timePrecision from 1339 to 1340 to distinguish between timeNames at time 3.95078e-06
Time = 3.950780097946136277327518204760536946196225471794605255126953125e-06
DILUPBiCG: Solving for rho, Initial residual = 3.68513e-05, Final residual = 1.19211e-09, No Iterations 2
max-min rho: 3784.75 -1.81282
max-min gamma: 1 0
DILUPBiCG: Solving for Ux, Initial residual = 0.00088791, Final residual = 2.56648e-11, No Iterations 3
#0 Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam211/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/opt/openfoam211/platforms/linux64GccDPO
What else I can do? Regards. |
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June 3, 2015, 21:04
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#14 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
By the by, I would like to change the title of the thread because it no longer reflects well the topic to solve but I don't know how...
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June 4, 2015, 04:51
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#15 |
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New Member
Al_th
Join Date: Apr 2015
Posts: 19
Rep Power: 11 |
Dear alvariten,
Don't worry, I'm also an Openfoam newbie (2/3 months only) Yes, what you are saying is true, it looks like your Courant number blows up, and that the dynamic delatT (I am assuming you are using adjustTimeStep in your controlDict file) is getting smaller and smaller in order to respect your maxCo condition. From what I've learned, if the Courant number blows up, it is not always (in my case, pretty much never) a problem of actually setting up deltaT. Especially when you use adjustTimeStep that is keeping an ideal deltaT at all time (until it blows up). What I am suggesting here, is that when the problem happens, it causes the Courant number to blow up, but the problem itself is caused by something else (non physical boundary conditions have a nice tendency to make everything crash pretty fast). Could you attach your case to the post so we can try it out ? PS : In the meantime, what you could do is to try to reduce the pressure gradient (set the inlet pressure to something really close to the outlet, see if it crashes or of the solution seems to converge, and increase it gradually. Last edited by al_th; June 4, 2015 at 06:03. |
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June 4, 2015, 07:40
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#16 |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Dear Al_th,
Here I show more details about the case: - Geometry mesh (2D -> 2 input and 1 output)   (I've changed mesh) - checkMesh log: Code:
Create time
Create polyMesh for time = 0
Time = 0
Mesh stats
points: 57460
internal points: 0
faces: 112969
internal faces: 55641
cells: 28080
boundary patches: 5
point zones: 0
face zones: 0
cell zones: 0
Overall number of cells of each type:
hexahedra: 27958
prisms: 0
wedges: 0
pyramids: 0
tet wedges: 0
tetrahedra: 0
polyhedra: 122
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
inlet 60 124 ok (non-closed singly connected)
outlet 72 146 ok (non-closed singly connected)
nozzleWall 218 438 ok (non-closed singly connected)
fixedWall 818 1640 ok (non-closed singly connected)
frontback 56160 57460 ok (non-closed singly connected)
Checking geometry...
Overall domain bounding box (-0.00081733 0 -1e-05) (0.00081733 0.00202762 1e-05)
Mesh (non-empty, non-wedge) directions (1 1 0)
Mesh (non-empty) directions (1 1 0)
All edges aligned with or perpendicular to non-empty directions.
Boundary openness (-4.75227e-18 2.00089e-17 2.02558e-15) OK.
Max cell openness = 5.78434e-16 OK.
Max aspect ratio = 7.27553 OK.
Minumum face area = 1.38739e-12. Maximum face area = 7.66506e-10. Face area magnitudes OK.
Min volume = 2.77478e-17. Max volume = 1.53301e-14. Total volume = 1.8426e-11. Cell volumes OK.
Mesh non-orthogonality Max: 47.2926 average: 12.1634
Non-orthogonality check OK.
Face pyramids OK.
Max skewness = 3.41278 OK.
Coupled point location match (average 0) OK.
Mesh OK.
End
cavitatingFoam log file - Numerical settings: controlDict fvScheme fvSolution - BC's from 0 folder: p pinlet file Code:
(
(0 3410000)
(0.00042 18130000)
);
(the case run in laminar model, but these are the set values for LESModel) k nuSgs And it's all I think. If I have leave something, let me know. Thanks for the interest. Regards.
Last edited by alvariten; June 8, 2015 at 14:51. |
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June 8, 2015, 05:59
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#17 | |
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Senior Member
Join Date: Mar 2015
Posts: 250
Rep Power: 12 |
Quote:
I am afraid I cannot help you here. Nethertheless I have two remarks: 1) I think the max-min rho etc. outputs are no problem per se. But regarding the values I can't judge them because I'm not familiar with these types of simulations. 2) I would try to run the calculation with turbulence turned off. This way you can be sure the problem's not turbulence related. Keep us updated, Kate |
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June 8, 2015, 11:31
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#18 |
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New Member
Al_th
Join Date: Apr 2015
Posts: 19
Rep Power: 11 |
Dear Alvariten.
I do not see anything unusual in what you gave me (Note that in your last post, half your links were pointing on the controlDict file !) Could you upload the full case so I can investigate ? |
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June 8, 2015, 15:00
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Nozzle 2D cavitaingFoam divergence
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#19 | |
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Member
alvaro
Join Date: Apr 2015
Posts: 33
Rep Power: 11 |
Quote:
I've fixed it! PD: I would like to change the main thread title (to "Nozzle 2D cavitatingFoam divergence" ) I think it's the right thing and it describes current topic better. But I don't find the way to do it. Is it possible to change by myself or is an Administrator/Moderator who has to do it? Regards. |
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July 2, 2015, 04:10
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#20 |
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New Member
sagar gurnani
Join Date: Jun 2015
Location: surat gujarat
Posts: 6
Rep Power: 11 |
Dear Alvariten,
How did you fixed your divergence problem.. could you please explain.. I am facing similar issues. Thanks |
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| Tags |
| cavitatingfoam, divergence |
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