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-   -   Continuity error cannot be removed by adjusting the outflow. Please check the velocit (https://www.cfd-online.com/Forums/openfoam-solving/147388-continuity-error-cannot-removed-adjusting-outflow-please-check-velocit.html)

range_rover January 20, 2015 03:17
Continuity error cannot be removed by adjusting the outflow. Please check the velocit
 
Hey guys

I am very new to openfoam, when i am using icofoam solver i have been facing this continuity error ,i am having an inflow in horizontal and outflow in vertical. i tried my ways to get over it , i am not able to can any body help me on this. :)

Error:

Continuity error cannot be removed by adjusting the outflow.
Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow.
Total flux : 376.432
Specified mass inflow : 20
Specified mass outflow : 7220
Adjustable mass outflow : 0


From function adjustPhi(surfaceScalarField&, const volVectorField&,volScalarField&)
in file cfdTools/general/adjustPhi/adjustPhi.C at line 118.

FOAM exiting

P-file

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

internalField uniform 0;

boundaryField
{
inlet
{
type zeroGradient;
}

outlet
{

type zeroGradient;
}

walls
{
type zeroGradient;
}
}


U-file

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

internalField uniform (0 0 0);

boundaryField
{
inlet
{
type fixedValue;
value uniform (10 0 0);
}

outlet
{
type fixedValue;
value uniform (0 0 20);

}

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

alexeym January 20, 2015 03:36
Hi,

It looks like area of the outlet is around 180 time greater than area of the inlet. Can you post screenshot of your mesh?

range_rover January 20, 2015 03:41
Yeah, you are true

I just figured it out, i adjusted my boundary conditions and it worked fine

thanks for your reply :)

crusen mind August 13, 2016 07:50
hi when i run simulation i am getting this error




PHP Code:
FOAM FATAL ERROR: 
[5] Continuity error cannot be removed by adjusting the outflow.
Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow.
Total flux              : 11.8087
Specified mass inflow   : 1.42626
Specified mass outflow  : 0.0135246
Adjustable mass outflow : 1.56994e-21 

Tobi August 13, 2016 08:56
This error tells you that it is not possible to adjust your fluxes. This happens if you define your problem weakly. So check your BC and make sure that you have physical BC.
E.g. (just one of a lot of examples)

  • if you define U and p to zeroGradient everywhere, think about how many solutions would be valid that the momentum is fulfilled
  • It is like setting pressure and velocity at the inlet, the outlet can now get a lot of valid results based on velocity / pressure (just for incompressible / low Mach)

crusen mind August 16, 2016 02:42
now i have increased my domain size, and i will use the boundary condition given in the propeller tutorial case.

crusen mind August 16, 2016 03:15
I am getting this error
PHP Code:
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  4.0                                   |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 4.0-665f1db4c1f1
Exec   : pimpleDyMFoam -parallel
Date   : Aug 16 2016
Time   : 12:42:08
Host   : "velan-OptiPlex-9020"
PID    : 3993
Case   : /home/velan/prop
nProcs : 8
Slaves : 
7
(
"velan-OptiPlex-9020.3994"
"velan-OptiPlex-9020.3995"
"velan-OptiPlex-9020.3996"
"velan-OptiPlex-9020.3997"
"velan-OptiPlex-9020.3998"
"velan-OptiPlex-9020.3999"
"velan-OptiPlex-9020.4000"
)

Pstream initialized with:
    floatTransfer      : 0
    nProcsSimpleSum    : 0
    commsType          : nonBlocking
    polling iterations : 0
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

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

Create mesh for time = 0

Selecting dynamicFvMesh solidBodyMotionFvMesh
Selecting solid-body motion function rotatingMotion
Applying solid body motion to cellZone innersmallcyclinder

PIMPLE: no residual control data found. Calculations will employ 2 corrector loops

Reading field p

Reading field U

Reading/calculating face flux field phi

AMI: Creating addressing and weights between 3324 source faces and 3324 target faces
AMI: Patch source sum(weights) min/max/average = 1, 1, 1
AMI: Patch target sum(weights) min/max/average = 1, 1, 1
Selecting incompressible transport model Newtonian
Selecting turbulence model type RAS
Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
    Cmu             0.09;
    C1              1.44;
    C2              1.92;
    C3              -0.33;
    sigmak          1;
    sigmaEps        1.3;
}

No MRF models present

Reading/calculating face velocity Uf

No finite volume options present

Courant Number mean: 4.99969e-06 max: 0.00139283
Reading surface description:
    zNormal
    isoQ
    propeller

forces forces:
    Not including porosity effects

Starting time loop

Courant Number mean: 4.95019e-06 max: 0.00137904
deltaT = 1.17647e-05
Time = 1.17647e-05

AMI: Creating addressing and weights between 3324 source faces and 3324 target faces
AMI: Patch source sum(weights) min/max/average = 0.999407, 1.0022, 0.999993
AMI: Patch target sum(weights) min/max/average = 0.999151, 1.00216, 0.999983
PIMPLE: iteration 1
smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 4.38333e-08, No Iterations 1
smoothSolver:  Solving for Uy, Initial residual = 1, Final residual = 4.70697e-08, No Iterations 1
smoothSolver:  Solving for Uz, Initial residual = 1, Final residual = 4.26061e-08, No Iterations 1
[2] #0  Foam::error::printStack(Foam::Ostream&)[3] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
 at ??:?
[3] #1  Foam::sigFpe::sigHandler(int)[2] #1  Foam::sigFpe::sigHandler(int) at ??:?
[3] #2  ? at ??:?
[2] #2  ? in "/lib/x86_64-linux-gnu/libc.so.6"
[2] #3   in "/lib/x86_64-linux-gnu/libc.so.6"
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[3] #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 at ??:?
[3] #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 at ??:?
[2] #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 at ??:?
[3] #5  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[2] #5  Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
[3] #6  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
[2] #6  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
[3] #7  Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
[3] #8   at ??:?
[2] #7  ?Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
[3] #9  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[3] #10   at ??:?
[2] #8  ?? at ??:?
[velan-OptiPlex-9020:03996] *** Process received signal ***
[velan-OptiPlex-9020:03996] Signal: Floating point exception (8)
[velan-OptiPlex-9020:03996] Signal code:  (-6)
[velan-OptiPlex-9020:03996] Failing at address: 0x3e800000f9c
[velan-OptiPlex-9020:03996] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x36cb0) [0x7fcf7703ecb0]
[velan-OptiPlex-9020:03996] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7fcf7703ec37]
[velan-OptiPlex-9020:03996] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x36cb0) [0x7fcf7703ecb0]
[velan-OptiPlex-9020:03996] [ 3] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5scaleERNS_5FieldIdEES3_RKNS_9lduMatrixERKNS_10FieldFieldIS1_dEERKNS_8UPtrListIKNS_17lduInterfaceFieldEEERKS2_h+0xb6) [0x7fcf78211976]
[velan-OptiPlex-9020:03996] [ 4] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver6VcycleERKNS_7PtrListINS_9lduMatrix8smootherEEERNS_5FieldIdEERKS8_S9_S9_S9_S9_S9_RNS1_IS8_EESD_h+0xe81) [0x7fcf78215ed1]
[velan-OptiPlex-9020:03996] [ 5] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5solveERNS_5FieldIdEERKS2_h+0x48b) [0x7fcf782179ab]
[velan-OptiPlex-9020:03996] [ 6] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x11e) [0x7fcf7b0e0afe]
[velan-OptiPlex-9020:03996] [ 7] pimpleDyMFoam(_ZN4Foam8fvMatrixIdE5solveERKNS_10dictionaryE+0x108) [0x466888]
[velan-OptiPlex-9020:03996] [ 8] pimpleDyMFoam() [0x425ce9]
[velan-OptiPlex-9020:03996] [ 9] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7fcf77029f45]
[velan-OptiPlex-9020:03996] [10] pimpleDyMFoam() [0x4273a7]
[velan-OptiPlex-9020:03996] *** End of error message ***
 at ??:?
[2] #9  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[2] #10  ? at ??:?
[velan-OptiPlex-9020:03995] *** Process received signal ***
[velan-OptiPlex-9020:03995] Signal: Floating point exception (8)
[velan-OptiPlex-9020:03995] Signal code:  (-6)
[velan-OptiPlex-9020:03995] Failing at address: 0x3e800000f9b
[velan-OptiPlex-9020:03995] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x36cb0) [0x7fe0d3628cb0]
[velan-OptiPlex-9020:03995] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37) [0x7fe0d3628c37]
[velan-OptiPlex-9020:03995] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x36cb0) [0x7fe0d3628cb0]
[velan-OptiPlex-9020:03995] [ 3] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5scaleERNS_5FieldIdEES3_RKNS_9lduMatrixERKNS_10FieldFieldIS1_dEERKNS_8UPtrListIKNS_17lduInterfaceFieldEEERKS2_h+0xb6) [0x7fe0d47fb976]
[velan-OptiPlex-9020:03995] [ 4] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver6VcycleERKNS_7PtrListINS_9lduMatrix8smootherEEERNS_5FieldIdEERKS8_S9_S9_S9_S9_S9_RNS1_IS8_EESD_h+0xe81) [0x7fe0d47ffed1]
[velan-OptiPlex-9020:03995] [ 5] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam10GAMGSolver5solveERNS_5FieldIdEERKS2_h+0x48b) [0x7fe0d48019ab]
[velan-OptiPlex-9020:03995] [ 6] /opt/openfoam4/platforms/linux64GccDPInt32Opt/lib/libfiniteVolume.so(_ZN4Foam8fvMatrixIdE15solveSegregatedERKNS_10dictionaryE+0x11e) [0x7fe0d76caafe]
[velan-OptiPlex-9020:03995] [ 7] pimpleDyMFoam(_ZN4Foam8fvMatrixIdE5solveERKNS_10dictionaryE+0x108) [0x466888]
[velan-OptiPlex-9020:03995] [ 8] pimpleDyMFoam() [0x425ce9]
[velan-OptiPlex-9020:03995] [ 9] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf5) [0x7fe0d3613f45]
[velan-OptiPlex-9020:03995] [10] pimpleDyMFoam() [0x4273a7]
[velan-OptiPlex-9020:03995] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 3 with PID 3996 on node velan-OptiPlex-9020 exited on signal 8 (Floating point exception).
-------------------------------------------------------------------------- 

crusen mind August 17, 2016 01:12
when i dont supply velocity at inlet my simulation is running


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