[hcen]

Hi everyone,

I am a newbie to OpenFoam, and am now trying to simulate a compressed air-water two phase pipe flow.

I've a mesh created from ICEM with only hex cells. The solver have been crashing and I have no clue what is leading to that. The model is pre-filled with water and has one compressed air inlet and two outlets. Below is the message from terminal. Could anyone take a look and give me a few advises? Thx!

Courant Number mean: 0.00344514823 max: 0.102423844
Max Ur Courant Number = 0.809298941
deltaT = 3.73662022e-06
Time = 0.125824067

PIMPLE: iteration 1
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0.0454209699 Min(alpha.air) = 2.97973812e-316 Max(alpha.air) = 1
Constructing momentum equations
smoothSolver: Solving for e.air, Initial residual = 0.000370432209, Final residual = 4.56780784e-09, No Iterations 2
smoothSolver: Solving for e.water, Initial residual = 3.72096286e-07, Final residual = 5.83454128e-11, No Iterations 1
min T.air -51.5335211
min T.water 208.307104
GAMG: Solving for p_rgh, Initial residual = 0.000283639836, Final residual = 1.04823569e-10, No Iterations 2
PIMPLE: iteration 2
MULES: Solving for alpha.air
MULES: Solving for alpha.air
alpha.air volume fraction = 0.0454209586 Min(alpha.air) = -3.97078944e-17 Max(alpha.air) = 1
Constructing momentum equations
[9] #0 Foam::error:rintStack(Foam::Ostream&)[11] #0 Foam::error:rintStack(Foam::Ostream&) at ??:?
[9] #1 Foam::sigFpe::sigHandler(int) at ??:?
[11] #1 Foam::sigFpe::sigHandler(int) at ??:?
[9] #2 ? at ??:?
[11] #2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
[9] #3 ? in "/lib/x86_64-linux-gnu/libc.so.6"
[11] #3 ? in "/lib/x86_64-linux-gnu/libm.so.6"
[9] #4 pow in "/lib/x86_64-linux-gnu/libm.so.6"
[11] #4 pow in "/lib/x86_64-linux-gnu/libm.so.6"
[9] #5 Foam:ow(Foam::Field<double>&, Foam::UList<double> const&, double const&) in "/lib/x86_64-linux-gnu/libm.so.6"
[11] #5 Foam:ow(Foam::Field<double>&, Foam::UList<double> const&, double const&) at ??:?
[9] #6 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam:ow<Foam::fvPatchField, Foam::volMesh>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::dimensioned<double> const&) at ??:?
[9] #7 Foam::dragModels::SchillerNaumann::CdRe() const at ??:?
[11] #6 Foam::tmp<Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> > Foam:ow<Foam::fvPatchField, Foam::volMesh>(Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::dimensioned<double> const&) at ??:?
[9] #8 Foam::dragModel::Ki() const at ??:?
[11] #7 Foam::dragModels::SchillerNaumann::CdRe() const at ??:?
[9] #9 Foam::dragModel::K() const at ??:?
[11] #8 Foam::dragModel::Ki() const at ??:?
[9] #10 Foam::BlendedInterfacialModel<Foam::dragModel>::K( ) const at ??:?
[9] #11 Foam::twoPhaseSystem::Kd() const at ??:?
[11] #9 Foam::dragModel::K() const at ??:?
[11] #10 Foam::BlendedInterfacialModel<Foam::dragModel>::K( ) const at ??:?
[11] #11 Foam::twoPhaseSystem::Kd() const at ??:?
[9] #12 ? at ??:?
[11] #12 at ??:?
[9] #13 __libc_start_main? in "/lib/x86_64-linux-gnu/libc.so.6"
[9] #14 ? at ??:?
[tande-Precision-Tower-7910:08931] *** Process received signal ***
[tande-Precision-Tower-7910:08931] Signal: Floating point exception (8)
[tande-Precision-Tower-7910:08931] Signal code: (-6)
[tande-Precision-Tower-7910:08931] Failing at address: 0x3e8000022e3
[tande-Precision-Tower-7910:08931] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x35250) [0x7f1e66adb250]
[tande-Precision-Tower-7910:08931] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7f1e66adb1c7]
[tande-Precision-Tower-7910:08931] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x35250) [0x7f1e66adb250]
[tande-Precision-Tower-7910:08931] [ 3] /lib/x86_64-linux-gnu/libm.so.6(+0x12f0c) [0x7f1e67099f0c]
[tande-Precision-Tower-7910:08931] [ 4] /lib/x86_64-linux-gnu/libm.so.6(pow+0x1c) [0x7f1e670ab44c]
[tande-Precision-Tower-7910:08931] [ 5] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam3powERNS_5FieldIdEERKNS_5UL istIdEERKd+0x38) [0x7f1e67f03348]
[tande-Precision-Tower-7910:08931] [ 6] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleTurbulenceModels.so(_ZN4Foam3powINS _12fvPatchFieldENS_7volMeshEEENS_3tmpINS_14Geometr icFieldIdT_T0_EEEERKS7_RKNS_11dimensionedIdEE+0x28 e) [0x7f1e6befb2ae]
[tande-Precision-Tower-7910:08931] [ 7] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleEulerianInterfacialModels.so(_ZNK4F oam10dragModels15SchillerNaumann4CdReEv+0x1d0) [0x7f1e6b0634a0]
[tande-Precision-Tower-7910:08931] [ 8] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleEulerianInterfacialModels.so(_ZNK4F oam9dragModel2KiEv+0x132) [0x7f1e6b02a1f2]
[tande-Precision-Tower-7910:08931] [ 9] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleEulerianInterfacialModels.so(_ZNK4F oam9dragModel1KEv+0x2e) [0x7f1e6b029ffe]
[tande-Precision-Tower-7910:08931] [10] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleTwoPhaseSystem.so(_ZNK4Foam23Blende dInterfacialModelINS_9dragModelEE1KEv+0x4a3) [0x7f1e6b450453]
[tande-Precision-Tower-7910:08931] [11] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleTwoPhaseSystem.so(_ZNK4Foam14twoPha seSystem2KdEv+0x32) [0x7f1e6b436042]
[tande-Precision-Tower-7910:08931] [12] twoPhaseEulerFoam() [0x43510b]
[tande-Precision-Tower-7910:08931] [13] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0) [0x7f1e66ac6ac0]
[tande-Precision-Tower-7910:08931] [14] twoPhaseEulerFoam() [0x4496a9]
[tande-Precision-Tower-7910:08931] *** End of error message ***
at ??:?
[11] #13 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[11] #14 ? at ??:?
[tande-Precision-Tower-7910:08933] *** Process received signal ***
[tande-Precision-Tower-7910:08933] Signal: Floating point exception (8)
[tande-Precision-Tower-7910:08933] Signal code: (-6)
[tande-Precision-Tower-7910:08933] Failing at address: 0x3e8000022e5
[tande-Precision-Tower-7910:08933] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x35250) [0x7fcddfb32250]
[tande-Precision-Tower-7910:08933] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7fcddfb321c7]
[tande-Precision-Tower-7910:08933] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x35250) [0x7fcddfb32250]
[tande-Precision-Tower-7910:08933] [ 3] /lib/x86_64-linux-gnu/libm.so.6(+0x12f0c) [0x7fcde00f0f0c]
[tande-Precision-Tower-7910:08933] [ 4] /lib/x86_64-linux-gnu/libm.so.6(pow+0x1c) [0x7fcde010244c]
[tande-Precision-Tower-7910:08933] [ 5] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam3powERNS_5FieldIdEERKNS_5UL istIdEERKd+0x38) [0x7fcde0f5a348]
[tande-Precision-Tower-7910:08933] [ 6] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleTurbulenceModels.so(_ZN4Foam3powINS _12fvPatchFieldENS_7volMeshEEENS_3tmpINS_14Geometr icFieldIdT_T0_EEEERKS7_RKNS_11dimensionedIdEE+0x22 e) [0x7fcde4f5224e]
[tande-Precision-Tower-7910:08933] [ 7] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleEulerianInterfacialModels.so(_ZNK4F oam10dragModels15SchillerNaumann4CdReEv+0x1d0) [0x7fcde40ba4a0]
[tande-Precision-Tower-7910:08933] [ 8] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleEulerianInterfacialModels.so(_ZNK4F oam9dragModel2KiEv+0x132) [0x7fcde40811f2]
[tande-Precision-Tower-7910:08933] [ 9] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleEulerianInterfacialModels.so(_ZNK4F oam9dragModel1KEv+0x2e) [0x7fcde4080ffe]
[tande-Precision-Tower-7910:08933] [10] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleTwoPhaseSystem.so(_ZNK4Foam23Blende dInterfacialModelINS_9dragModelEE1KEv+0x4a3) [0x7fcde44a7453]
[tande-Precision-Tower-7910:08933] [11] /home/tande/OpenFOAM/OpenFOAM-v3.0+/platforms/linux64GccDPInt32Opt/lib/libcompressibleTwoPhaseSystem.so(_ZNK4Foam14twoPha seSystem2KdEv+0x32) [0x7fcde448d042]
[tande-Precision-Tower-7910:08933] [12] twoPhaseEulerFoam() [0x43510b]
[tande-Precision-Tower-7910:08933] [13] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0) [0x7fcddfb1dac0]
[tande-Precision-Tower-7910:08933] [14] twoPhaseEulerFoam() [0x4496a9]
[tande-Precision-Tower-7910:08933] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 9 with PID 8931 on node tande-Precision-Tower-7910 exited on signal 8 (Floating point exception).

Everything seemed fine to me. The residuals are small, reached with only 1 or 2 iterations. I just didn't understand what was causing the problem. Any suggestion would be appreciated!!!

Best,
HC

[mnikku]

Originally Posted by hcen

min T.air -51.5335211
min T.water 208.307104

Well, there's your problem. Your energy equation is probably not converging since you manage to get minus Kelvins. Reasons for this (from my experience) are related to boundary conditions, thought something else might cause this too.

[hcen]

Originally Posted by mnikku

Well, there's your problem. Your energy equation is probably not converging since you manage to get minus Kelvins. Reasons for this (from my experience) are related to boundary conditions, thought something else might cause this too.

Thanks man! I developed my set of boundary conditions from the tutorial Bubble Column. For
alpha air : fixed value - inlet; inletoutlet - outlet; zerogradient - walls;
p_rgh: fixedFluxPressure - inlet; totalPressure - outlet; zerogradient - walls;
T: fixedValue - inlet; inletOutlet - outlet; zerogradient - walls;
U_air: flowRateInletVelocity - inlet; pressureInletOutletVelocity - outlet;

The rest of parameters are pretty much the same as the tutorial. I just couldn't figure out what might be the problem. Would you be able to take a look at it? Much appreciated!

Best,
HCen

[mnikku]

You should post some more information about your case for anyone to be able to help you further.
You could test your case with the bubble column boundary conditions if those work with your case.

[arianam]

As mentioned above, the solution diverging. If you keep the track of pressure(e.g. min(p)) , the constant decrease or increase in pressure should be observed.
I should warn you that twoPhaseEulerFoam solver diverges easily if you do not keep your CO and maxdeltaT low enough.
My suggestions:
1. check if you do correctly setFields
2. Lower your CO and maxDeltaT in system/controlDict (e.g. CO to 0.1 and maxDeltaT to 1e-4)
3. Try to under-relax your iteration ( system/fvSolution relaxationFactors)
Hope this might help you!
M. Ariana

[rakesh927]

Originally Posted by arianam

As mentioned above, the solution diverging. If you keep the track of pressure(e.g. min(p)) , the constant decrease or increase in pressure should be observed.
I should warn you that twoPhaseEulerFoam solver diverges easily if you do not keep your CO and maxdeltaT low enough.
My suggestions:
1. check if you do correctly setFields
2. Lower your CO and maxDeltaT in system/controlDict (e.g. CO to 0.1 and maxDeltaT to 1e-4)
3. Try to under-relax your iteration ( system/fvSolution relaxationFactors)
Hope this might help you!
M. Ariana

Hi friends,

I am also having similar problem, where twoPhaseEulerFoam crashes after some time. I have found that, before it gets crashed, Max (alpha.air) value jumps inordinately to 1e7 and max. Courant Number is around 8. Although I set maxCo to 0.1 and maxDeltaT to 0.01 is controlDict file.

Awaiting for experts comments.
Thanks

[mnikku]

And the fvSolution? Are you obtaining convergence or just simulation couple of iterations and accepting whatever is the result of that?

[rakesh927]

Hi,

I am attaching the fvSolution file and convergence plot for p_rgh_0.
Kindly suggest me.

[mnikku]

Please try the search function in these forums, it would have probably found this:
http://www.cfd-online.com/Forums/ope...tml#post607189

[sujata]

How did u plot the convergence plot?

[mnikku]

Originally Posted by sujata

How did u plot the convergence plot?

You can use whatever plotting tools (Matlab etc) with the logged residual data. In you controlDict, inside functions you have to add

#includeFunc  residuals

In the system -folder add file residuals, where you specify what residuals to log. These are logged to folder postProcessing/residuals/<starting time step>/residuals.dat . Use this file for plotting.

See User's Guide section 6.3.4.

[sujata]

Originally Posted by mnikku

You can use whatever plotting tools (Matlab etc) with the logged residual data. In you controlDict, inside functions you have to add

#includeFunc  residuals

In the system -folder add file residuals, where you specify what residuals to log. These are logged to folder postProcessing/residuals/<starting time step>/residuals.dat . Use this file for plotting.

See User's Guide section 6.3.4.

Thanks for the help, will do that and let you know. So, I am a new OpenFOAM user and trying to solve multiphase flow problem with reactingMultiphaseEulerfoam solver. I want to know how to print the drag, lift forces? I saw that there is some center of rotation (CofR). How do I get the direction? Also, I want to print the Cd and Cl. Please, anyone, help me with that. I am using OpenFoam version 4.1.

[geth03]

Originally Posted by sujata

Thanks for the help, will do that and let you know. So, I am a new OpenFOAM user and trying to solve multiphase flow problem with reactingMultiphaseEulerfoam solver. I want to know how to print the drag, lift forces? I saw that there is some center of rotation (CofR). How do I get the direction? Also, I want to print the Cd and Cl. Please, anyone, help me with that. I am using OpenFoam version 4.1.

i know that for openfoam version 6 and 7, there are functions which try to do that. i would suggest updating your version and then checking out
the functionObjects-directory in applications->solvers->multiphase->reactingEulerFoam.

you should be able to print out the phase forces by adding a function to controlDict:
phaseForces.water
{
type phaseForces;
libs ("libreactingEulerFoamFunctionObjects.so");
writeControl outputTime;
writeInterval 1;
log false;
...
phaseName water;
}

[Ardali]

As many people sees this problem, I give short answer to this.
If you do not need energy equation discard it in the solver.

If you need it specify correct boundary conditions in T files.

diameterModel in phaseProperties matters as well.
If comprisibility matters to you a lot, e.g.sonic jet or so on, It will be reflected in p_rgh, therefore it wont be a sudden crash. Anyhow, small courant number in the order of 0.1 may help too.
Good luck
Ardalan

[jagan1mohan]

Hello Ardali, I'm using twoPhaseEulerFoam (2PEF) and I do not want to use energy equation as my flow is isothermal and it is incompressible.


1. Can you elaborate a bit more on turning off energy equation in this solver?



I have used 288K for all temperature fields initialization, BCs for both gas and particles but there is an energy transfer and temperature varies from 250 K to 320 K.

Thank you,
Jagan Mohan.

[Ardali]

Originally Posted by jagan1mohan

Hello Ardali, I'm using twoPhaseEulerFoam (2PEF) and I do not want to use energy equation as my flow is isothermal and it is incompressible.


1. Can you elaborate a bit more on turning off energy equation in this solver?



I have used 288K for all temperature fields initialization, BCs for both gas and particles but there is an energy transfer and temperature varies from 250 K to 320 K.

Thank you,
Jagan Mohan.

Yes, sure,
there two lines in the twoPhaseEulerFoam which says

#include "EEqns.H"
Only comment those two lines and it works fine.

[jagan1mohan]

Thank you Ardali, I've commented out following two lines as shown below and recompiling it now.


if (faceMomentum) {
....
// #include "EEqns.H"
....

}
else {
....
// #include "EEqns.H"
....

}


So, now I do not have to include the T.particles and T.air files in 0 directory? Also, could you take a look at my other request on the forum.



twoPhaseEulerFoam inlet velocity


Thank you,
Jagan Mohan.

[sujata]

Hello, foamers

I am using OpenFoam 4.1 and using reactingMultiphaseEulerFoam and using the drag, lift, virtual mass, and turbulent dispersion force. I am time averaging it after 40 s to 80s. But after 75 s it doesn't run anymore and shows the following error. Please help me. I am unable to solve it.

[1] #0 Foam::error:rintStack(Foam::Ostream&) at ??:?
[1] #1 Foam::sigFpe::sigHandler(int) at ??:?
[1] #2 ? in "/lib64/libpthread.so.0"
[1] #3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) at ??:?
[1] #4 Foam::tmp<Foam::GeometricField<double, Foam::volMesh> > Foam::sqrt<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::volMesh> > const&) at ??:?
[1] #5 Foam::heatTransferModels::RanzMarshall2::K(double) const at ??:?
[1] #6 Foam::BlendedInterfacialModel<Foam::heatTransferMo del>::K() const at ??:?
[1] #7 Foam::HeatTransferPhaseSystem<Foam::MomentumTransf erPhaseSystem<Foam::multiphaseSystem> >::heatTransfer() const at ??:?
[1] #8 ? at ??:?
[1] #9 __libc_start_main in "/lib64/libc.so.6"
[1] #10 ? at ??:?

[geth03]

Originally Posted by sujata

Hello, foamers

I am using OpenFoam 4.1 and using reactingMultiphaseEulerFoam and using the drag, lift, virtual mass, and turbulent dispersion force. I am time averaging it after 40 s to 80s. But after 75 s it doesn't run anymore and shows the following error. Please help me. I am unable to solve it.

[1] #0 Foam::error:rintStack(Foam::Ostream&) at ??:?
[1] #1 Foam::sigFpe::sigHandler(int) at ??:?
[1] #2 ? in "/lib64/libpthread.so.0"
[1] #3 Foam::sqrt(Foam::Field<double>&, Foam::UList<double> const&) at ??:?
[1] #4 Foam::tmp<Foam::GeometricField<double, Foam::volMesh> > Foam::sqrt<Foam::fvPatchField, Foam::volMesh>(Foam::tmp<Foam::GeometricField<doub le, Foam::volMesh> > const&) at ??:?
[1] #5 Foam::heatTransferModels::RanzMarshall2::K(double) const at ??:?
[1] #6 Foam::BlendedInterfacialModel<Foam::heatTransferMo del>::K() const at ??:?
[1] #7 Foam::HeatTransferPhaseSystem<Foam::MomentumTransf erPhaseSystem<Foam::multiphaseSystem> >::heatTransfer() const at ??:?
[1] #8 ? at ??:?
[1] #9 __libc_start_main in "/lib64/libc.so.6"
[1] #10 ? at ??:?

can you also post the prints just before the error message?
this way i can see at which equation the crash occured.