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Old   April 17, 2008, 23:14
Default Hi Eric and Mark when i def
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wayne.zhang
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Hi Eric and Mark

when i define the massflowrate in 0/U as :

INLET
{
type massFlowRateInletVelocity;
massFlowRate 0.71;
value uniform (0 0 0);
}


the case was end with the error after 500 steps. if i change to the:

INLET
{
type massFlowRateInletVelocity;
massFlowRate 0.71;
value uniform (0 0 0.71);
}

the error will after more than 1000 steps. the error message is here:

[0] #0 [1] #0 Foam::error::printStack(Foam:stream&)Foam::error::printStack(Foam:stream&) in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so"
[0] #1 Foam::sigFpe::sigFpeHandler(int) in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so"
[1] #1 Foam::sigFpe::sigFpeHandler(int) in "/home/waynezw0618/ in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so"
[0] #2 OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libOpenFOAM.so"
[1] #2 ???? in "/lib64/libc.so.6"
in "/lib64/libc.so.6"
[0] #3 void Foam::processorLduInterface::compressedSend<foam:: vector<double> >(Foam::UList<foam::vector<double> > const&, bool) const[1] #3 void Foam::processorLduInterface::compressedSend<foam:: vector<double> >(Foam::UList<foam::vector<double> > const&, bool) const in in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[0] #4 Foam::processorFvPatchField<foam::vector<double> >::initEvaluate(bool)"/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDP Opt/libfiniteVolume.so"
[1] #4 Foam::processorFvPatchField<foam::vector<double> >::initEvaluate(bool) in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[0] #5 in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[1] #5 Foam::GeometricField<foam::vector<double>, Foam::fvPatchField, Foam::volMesh>::GeometricBoundaryField::evaluate() Foam::GeometricField<foam::vec tor<double>, Foam::fvPatchField, Foam::volMesh>::GeometricBoundaryField::evaluate() in "/home/waynezw0618/OpenFOAM/waynezw0618-1.4.1/applications/bin/linux64GccDPOpt/M RFSimpleFoam"
[0] #6 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/waynezw0618/OpenFOAM/waynezw0618-1.4.1/applications/bin/linux64GccDPOpt/M RFSimpleFoam"
[1] #6 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/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[0] #7 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/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[1] #7 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/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[0] #8 Foam::fv::gaussDivScheme<foam::tensor<double> >::fvcDiv(Foam::GeometricField<foam::tensor<double >, Foam::fvPatchField, Foam::volMesh> const&) in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[1] #8 Foam::fv::gaussDivScheme<foam::tensor<double> >::fvcDiv(Foam::GeometricField<foam::tensor<double >, Foam::fvPatchField, Foam::volMesh> const&) in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[0] #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::GeometricField<foam::tensor<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::word const&) in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.s o"
[1] #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::GeometricField<foam::tensor<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::word const&) in in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressible TurbulenceModels.so"
[0] #10 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&)"/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompr essibleTurbulenceModels.so"
[1] #10 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/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressible TurbulenceModels.so"
[1] #11 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/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressible TurbulenceModels.so"
[0] #11 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/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressible TurbulenceModels.so"
[1] #12 Foam::turbulenceModels::kEpsilon::divR(Foam::Geome tricField<foam::vector<double> , Foam::fvPatchField, Foam::volMesh>&) const in in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressible TurbulenceModels.so"
[0] #12 Foam::turbulenceModels::kEpsilon::divR(Foam::Geome tricField<foam::vector<double> , Foam::fvPatchField, Foam::volMesh>&) const"/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompres sibleTurbulenceModels.so"
[1] #13 in "/home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressible TurbulenceModels.so"
[0] #13 main in main"/home/waynezw0618/OpenFOAM/waynezw0618-1.4.1/applications/bin/linux64GccDPO pt/MRFSimpleFoam"
[1] #14 __libc_start_main in "/lib64/libc.so.6"
[1] #15 in "/home/waynezw0618/OpenFOAM/waynezw0618-1.4.1/applications/bin/linux64GccDPOpt/M RFSimpleFoam"
[0] #14 __libc_start_main__gxx_personality_v0 in "/lib64/libc.so.6"
[0] #15 in "/home/waynezw0618/OpenFOAM/waynezw0618-1.4.1/applications/bin/linux64GccDPOpt/M RFSimpleFoam"
[wayne:08021] *** Process received signal ***
[wayne:08021] Signal: Floating point exception (8)
[wayne:08021] Signal code: (-6)
[wayne:08021] Failing at address: 0x3ea00001f55
__gxx_personality_v0[wayne:08021] [ 0] /lib64/libc.so.6 [0x2b1e537fcb20]
in "/home/waynezw0618/OpenFOAM/waynezw0618-1.4.1/applications/bin/linux64GccDPOpt/M RFSimpleFoam"
[wayne:08020] *** Process received signal ***
[wayne:08020] Signal: Floating point exception (8)
[wayne:08020] Signal code: (-6)
[wayne:08020] Failing at address: 0x3ea00001f54
[wayne:08020] [ 0] /lib64/libc.so.6 [0x2ae4f8143b20]
[wayne:08020] [ 1] /lib64/libc.so.6(gsignal+0x35) [0x2ae4f8143aa5]
[wayne:08020] [ 2] /lib64/libc.so.6 [0x2ae4f8143b20]
[wayne:08020] [ 3] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZNK4Foam21processorLduInterface14compressedSendI NS_6VectorIdEEEEvRKNS_5UListIT _EEb+0x92) [0x2ae4f6a71072]
[wayne:08020] [ 4] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam21processorFvPatchFieldINS_6VectorIdEEE12 initEvaluateEb+0x65) [0x2ae4f6a74055]
[wayne:08020] [ 5] MRFSimpleFoam(_ZN4Foam14GeometricFieldINS_6VectorI dEENS_12fvPatchFieldENS_7volMe shEE22GeometricBoundaryField8evaluateEv+0x85) [0x420cd5]
[wayne:08020] [ 6] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam3fvc16surfaceIntegrateINS_6VectorIdEEEENS _3tmpINS_14GeometricFieldIT_NS _12fvPatchFieldENS_7volMeshEEEEERKNS5_IS6_NS_13fvs PatchFieldENS_11surfaceMeshEEE +0x3b0) [0x2ae4f6f39610]
[wayne:08020] [ 7] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam3fvc16surfaceIntegrateINS_6VectorIdEEEENS _3tmpINS_14GeometricFieldIT_NS _12fvPatchFieldENS_7volMeshEEEEERKNS4_INS5_IS6_NS_ 13fvsPatchFieldENS_11surfaceMe shEEEEE+0x2f) [0x2ae4f6f397bf]
[wayne:08020] [ 8] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam2fv14gaussDivSchemeINS_6TensorIdEEE6fvcDi vERKNS_14GeometricFieldIS3_NS_ 12fvPatchFieldENS_7volMeshEEE+0x69) [0x2ae4f6f3a7c9]
[wayne:08020] [ 9] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZN4Foam3fvc3divINS_6TensorIdEE EENS_3tmpINS_14GeometricFieldI NS_12innerProductINS_6VectorIdEET_E4typeENS_12fvPa tchFieldENS_7v[wayne:08021] [ 1] /lib64/libc.so.6(gsignal+0x35) [0x2b1e537fcaa5]
[wayne:08021] [ 2] /lib64/libc.so.6 [0x2b1e537fcb20]
[wayne:08021] [ 3] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZNK4Foam21processorLduInterface14compressedSendI NS_6VectorIdEEEEvRKNS_5UListIT _EEb+0x92) [0x2b1e5212a072]
[wayne:08021] [ 4] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam21processorFvPatchFieldINS_6VectorIdEEE12 initEvaluateEb+0x65) [0x2b1e5212d055]
[wayne:08021] [ 5] MRFSimpleFoam(_ZN4Foam14GeometricFieldINS_6VectorI dEENS_12fvPatchFieldENS_7volMe shEE22GeometricBoundaryField8evaluateEv+0x85) [0x420cd5]
[wayne:08021] [ 6] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam3fvc16surfaceIntegrateINS_6VectorIdEEEENS _3tmpINS_14GeometricFieldIT_NS _12fvPatchFieldENS_7volMeshEEEEERKNS5_IS6_NS_13fvs PatchFieldENS_11surfaceMeshEEE +0x3b0) [0x2b1e525f2610]
[wayne:08021] [ 7] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam3fvc16surfaceIntegrateINS_6VectorIdEEEENS _3tmpINS_14GeometricFieldIT_NS _12fvPatchFieldENS_7volMeshEEEEERKNS4_INS5_IS6_NS_ 13fvsPatchFieldENS_11surfaceMe shEEEEE+0x2f) [0x2b1e525f27bf]
[wayne:08021] [ 8] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libfiniteVolume.so (_ZN4Foam2fv14gaussDivSchemeINS_6TensorIdEEE6fvcDi vERKNS_14GeometricFieldIS3_NS_ 12fvPatchFieldENS_7volMeshEEE+0x69) [0x2b1e525f37c9]
[wayne:08021] [ 9] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZN4Foam3fvc3divINS_6TensorIdEE EENS_3tmpINS_14GeometricFieldI NS_12innerProductINS_6VectorIdEET_E4typeENS_12fvPa tchFieldENS_7volMeshEEEEERKNS5 _IS9_SC_SD_EERKNS_4wordE+0x68) [0x2b1e517d0da8]
[wayne:08021] [10] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZN4Foam3fvc3divINS_6TensorIdEE EENS_3tmpINS_14GeometricFieldI NS_12innerProductINS_6VectorIdEET_E4typeENS_12fvPa tchFieldENS_7volMeshEEEEERKNS5 _IS9_SC_SD_EE+0x1d2) [0x2b1e517d2e22]
[wayne:08021] [11] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZN4Foam3fvc3divINS_6TensorIdEE EENS_3tmpINS_14GeometricFieldI NS_12innerProductINS_6VectorIdEET_E4typeENS_12fvPa tchFieldENS_7volMeshEEEEERKNS4 _INS5_IS9_SC_SD_EEEE+0x2f) [0x2b1e517d2eff]
[wayne:08021] [12] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZNK4Foam16turbulenceModels8kEp silon4divRERNS_14GeometricFiel dINS_6VectorIdEENS_12fvPatchFieldENS_7volMeshEEE+0 xa8) [0x2b1e518a1e58]
[wayne:08021] [13] MRFSimpleFoam [0x414a8d]
[wayne:08021] [14] /lib64/libc.so.6(__libc_start_main+0xf4) [0x2b1e537ea154]
[wayne:08021] [15] MRFSimpleFoam(__gxx_personality_v0+0xe1) [0x413049]
[wayne:08021] *** End of error message ***
olMeshEEEEERKNS5_IS9_SC_SD_EERKNS_4wordE+0x68) [0x2ae4f6117da8]
[wayne:08020] [10] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZN4Foam3fvc3divINS_6TensorIdEE EENS_3tmpINS_14GeometricFieldI NS_12innerProductINS_6VectorIdEET_E4typeENS_12fvPa tchFieldENS_7volMeshEEEEERKNS5 _IS9_SC_SD_EE+0x1d2) [0x2ae4f6119e22]
[wayne:08020] [11] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZN4Foam3fvc3divINS_6TensorIdEE EENS_3tmpINS_14GeometricFieldI NS_12innerProductINS_6VectorIdEET_E4typeENS_12fvPa tchFieldENS_7volMeshEEEEERKNS4 _INS5_IS9_SC_SD_EEEE+0x2f) [0x2ae4f6119eff]
[wayne:08020] [12] /home/waynezw0618/OpenFOAM/OpenFOAM-1.4.1/lib/linux64GccDPOpt/libincompressibleT urbulenceModels.so(_ZNK4Foam16turbulenceModels8kEp silon4divRERNS_14GeometricFiel dINS_6VectorIdEENS_12fvPatchFieldENS_7volMeshEEE+0 xa8) [0x2ae4f61e8e58]
[wayne:08020] [13] MRFSimpleFoam [0x414a8d]
[wayne:08020] [14] /lib64/libc.so.6(__libc_start_main+0xf4) [0x2ae4f8131154]
[wayne:08020] [15] MRFSimpleFoam(__gxx_personality_v0+0xe1) [0x413049]
[wayne:08020] *** End of error message ***
mpirun noticed that job rank 0 with PID 8020 on node wayne exited on signal 8 (Floating point exception).
1 additional process aborted (not shown)


how to define the last parameter?
type uniform (...)
thanks

wayne
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Old   October 6, 2008, 05:50
Default hi Everybody, I am doing this
  #42
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Mahendra
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hi Everybody,
I am doing this MRFSimpleFoam case with my blower mesh, I am giving inlet as mass flow rate.
Inlet
{
type massFlowRateInletVelocity;
massFlow uniform 7.64;
value uniform (0 0 0);
}
But I am getting this error and I am not able to understand it. Can anyone Please help me out of this?
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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;
alphaEps 0.76923;
}


Starting time loop

Time = 0.0002




gradientInternalCoeffs cannot be called for a genericFvPatchField (actual type massFlowRateInletVelocity)
on patch Inlet of field U in file "/home/ms.wankhede/OpenFOAM/ms.wankhede-1.5/tut/extra_blower/0/U"
You are probably trying to solve for a field with a generic boundary condition.

From function genericFvPatchField<type>::gradientInternalCoeffs( ) const
in file fields/fvPatchFields/basic/generic/genericFvPatchField.C at line 692.

FOAM exiting
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Old   October 6, 2008, 09:28
Default Hi Mahendra: in 1.5 it chan
  #43
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wayne.zhang
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Hi Mahendra:

in 1.5 it changeto :
00041 type flowRateInletVelocity;
00042 flowRate 0.2; // Volumetric/mass flow rate [m3/s or kg/s]
00043 value uniform (0 0 0); // placeholder

hope usefull

regards

yours wayne
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Old   October 6, 2008, 09:55
Default sorry it copied from flowRateI
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sorry it copied from flowRateInletVelocityFvPatchVectorField.H searched from doxygen.so remove the number before like this

type flowRateInletVelocity;
flowRate 0.2; // Volumetric/mass flow rate [m3/s or kg/s]
value uniform (0 0 0); // placeholder


i am not sure if it is volumetric or mass flow rate for the code deciding from dimention of phi.and i think the dimention of phi in MRFsimpleFoam is dimVelocity*dimArea so,it should be volumetric rate.

Dragos?is that right?


wayne
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Old   October 10, 2008, 03:55
Default Hm, I have to update myself wi
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Hm, I have to update myself with this!
For the moment I don't know the answer, but it sounds correct what you're saying. Actually, I think the volumetric flow should be specified for all the incompressible solvers, since they are using equations divided by density.

Dragos
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Old   May 22, 2009, 03:27
Default Higher Velocities in a given region of mixer
  #46
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Hi All


Can someone please point out where i am going wrong, and put in some suggestions. I am facing similar problem despite trying some of the solutions in this posts. The CFX has been able to give good results for the same mesh. I am struggling with openFoam.

Problem: Higher Velocities in a given region of mixer, which increases with each iteration. (see the figures, which shows high velocity near overflow over baffle).


I am running a steady state k-epsilon simulation of mixer region using MFRSimplefoam. It has two inlets at 'bottom zone' and an overflow outlet at top (as in figure) in 'tank zone', with impeller rotating at 22.94 rad/sec (200 rev/min) within 'impeller zone'. I have tried to do a lot of simulations but still getting very high velocities at a particular region near overflow outlet above baffles (see red in figure 3, and high values in fig 1 outlet). The Mesh is tetrahedral with a Max orthogonality of 68.285 and is checkMesh says okay. The details of simulation are as follows:

1. checkMesh output: Tetrahedra: 824991. Max aspect ratio = 8.56327 OK.
Mesh non-orthogonality Max: 68.285 average: 19.9527 Threshold = 70
Non-orthogonality check OK.
Max skewness = 1.02244 OK.

Does one need orthogonal correction for this. I have tried as in point 5.

2. The residuals gets settled at 1e-2 after reaching a minima of order 1e-3 for a brief period.

What are the value of residuals ppl are observing who are getting good results for MRFSimpleFoam? Are my residuals good for a mesh with large number of cells?

3. fvSchemes:
Gauss upwind divergence scheme for all; Laplacian: Gauss linear limited 0.3 for k,epsilon, as taking anything more than this causes unbouned epsilon, and Gauss linear limited 0.7 for momentum.

Any suggestions here too?


4. fvsolutions:
PCG for Pressure with GAMG preconditioner with tolerance around 1e-7. Smoothsolvers for k,eps,U with nsweeps = 2 and tolerance of 1e-8.

Do i have to increase number of sweeps. Can anyone please share his experiance with increasing this.

5. BC outlet and initailization: inletoutlet for k,epsilon; pressureinletoutlet for U, totalpressure for P. inlet: velocity inlet given, and zero gradients for rest of them. I have also tried initializing with potentialfoam , but end results is same. After 2000 iterations, there is a high velocity region, where velocity increases with each iteration.

I have tried with zerogradient schemes for others and simple pressure value at outlet. Moved on to imletoutlet after some suggestions.

5. Non-orthogonal correction: I have tried using 2-5 non-orthogonal corrections for this mesh.

Do i need more than that for the given mesh. what if at one small patch i have high non-orthogonality say max of 68 which is causing this.

6. Relaxation factor: 0.1 for all. I have tried changing this for all values.

Does any one has any suggestion what i should do for this. I read in one post that k,eps has been started with 0.01 relaxation for 200 iterations. Any suggestions on this.

I really appreciate your help. Please put in some responses. Thank you.
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Old   June 2, 2009, 05:46
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change your mesh. may be a good choice.
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Old   November 11, 2009, 09:37
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hi Eric,
i have an impeller of pump meshed by gambit,which is an unstructured mesh.and it is successfully calculated by fluent,while it was imported into OpenFOAM-1.5,it went divergenced after dozens of steps.the steps i adopted are as follow:
1.dos2units *.msh
2.fluent3DMeshToFoam *.msh -case <dir>
3.transformPoints -case <dir> "(0.001 0.001 0.001)"
4.cellSet,faceSet,setsToZones -noFlipMap,
5.setup the MRF,0 folder ,transportProperties and controlDict
6.MRFSimpleFOAM
after several steps it goes divergenced,i don't know what is the cause of divergence,can it be the mesh?i saw someone use structured mesh calculated successfully.can this solve support the unstructured mesh? would you mind give me some advices? appreciate!
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Old   November 11, 2009, 09:44
Default an unstructured mesh calculated by MRFSimpleFOAM go divergenced ,what can i do?
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[QUOTE=lillberg;200069]
hi lillberg,
i have an impeller of pump meshed by gambit,which is an unstructured mesh.and it is successfully calculated by fluent,while it was imported into OpenFOAM-1.5,it went divergenced after dozens of steps.the steps i adopted are as follow:
1.dos2units *.msh
2.fluent3DMeshToFoam *.msh -case <dir>
3.transformPoints -case <dir> "(0.001 0.001 0.001)"
4.cellSet,faceSet,setsToZones -noFlipMap,
5.setup the MRF,0 folder ,transportProperties and controlDict
6.MRFSimpleFOAM
after several steps it goes divergenced,i don't know what is the cause of divergence,can it be the mesh?i saw someone use structured mesh calculated successfully.can this solve support the unstructured mesh? would you mind give me some advices? appreciate!
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Old   December 21, 2009, 05:05
Default try to change div schemes
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Hi Wayne,
I had faced a similar problem with MRFSimpleFoam, I could solve by changing the fvSchemes. Try the upwind instead of limitedlinear

divSchemes

{

default none;

div(phi,U) Gauss limitedLinearV 1; // Gauss linearUpwind Gauss

div(phi,k) Gauss limitedLinear 1; // Gauss upwind

div(phi,epsilon) Gauss limitedLinear 1; // Gauss upwind

div((nuEff*dev(grad(U).T()))) Gauss linear;

}
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Old   December 21, 2009, 10:45
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hi,
'Gauss linearUpwind Gauss' belongs to which of discrete formats?what is the principle?would you mind to tell me?

regards
jennifer
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