CFD Online Discussion Forums (https://www.cfd-online.com/Forums/)
-   OpenFOAM Running, Solving & CFD (https://www.cfd-online.com/Forums/openfoam-solving/)
-   -   what is the meaning of this?!??!!? (https://www.cfd-online.com/Forums/openfoam-solving/107746-what-meaning.html)

what is the meaning of this?!??!!?

Hi everybody

I'm modeling a rotating square between water and air. when I run my model, the following messages appeared in my terminal:
Code:

```solidBodyMotionFunctions::rotatingMotion::transformation(): Time = 0.0827406 transformation: ((0 0 0) (-0.856565 (0 0 0.51604))) Execution time for mesh.update() = 0.05 s time step continuity errors : sum local = 5.19359e-14, global = 1.91199e-15, cumulative = 1.45354e-06 GAMGPCG:  Solving for pcorr, Initial residual = 1, Final residual = 3.28882e-06, No Iterations 9 time step continuity errors : sum local = 3.27857e-15, global = -4.81172e-17, cumulative = 1.45354e-06 MULES: Solving for alpha1 Liquid phase volume fraction = 0.129117  Min(alpha1) = -3.3351e-36  Max(alpha1) = 0.999977 MULES: Solving for alpha1 Liquid phase volume fraction = 0.129169  Min(alpha1) = -3.33127e-36  Max(alpha1) = 0.999977 MULES: Solving for alpha1 Liquid phase volume fraction = 0.12922  Min(alpha1) = -3.32675e-36  Max(alpha1) = 0.999977 GAMG:  Solving for p_rgh, Initial residual = 0.0226012, Final residual = 0.000126703, No Iterations 3 time step continuity errors : sum local = 1.35142e-09, global = 7.04088e-12, cumulative = 1.45355e-06 GAMGPCG:  Solving for p_rgh, Initial residual = 0.00713841, Final residual = 5.44584e-09, No Iterations 6 time step continuity errors : sum local = 5.81134e-14, global = 2.97304e-16, cumulative = 1.45355e-06 smoothSolver:  Solving for epsilon, Initial residual = 0.00084478, Final residual = 7.54014e-08, No Iterations 3 smoothSolver:  Solving for k, Initial residual = 0.000782825, Final residual = 2.30447e-07, No Iterations 3 ExecutionTime = 305.2 s  ClockTime = 306 s Interface Courant Number mean: 0.0379477 max: 0.490161 Courant Number mean: 0.248671 max: 0.499417 deltaT = 7.19143e-05 Time = 0.0828125 solidBodyMotionFunctions::rotatingMotion::transformation(): Time = 0.0828125 transformation: ((0 0 0) (-0.857728 (0 0 0.514103))) Execution time for mesh.update() = 0.04 s time step continuity errors : sum local = 5.86878e-14, global = 2.49004e-16, cumulative = 1.45355e-06```
can anybody help me?
what is the meaning of this message:
Code:

`time step continuity errors : sum local = 5.86878e-14, global = 2.49004e-16, cumulative = 1.45355e-06`
thank you

 ata October 6, 2012 07:34

Hi
I think
sum local is absolute summation of continuty error in all CVs at present time step.
global is summation of continuty error in all CVs at present time stem and
cumulative is summation of global continuity errors from the first time step.

Quote:
 Originally Posted by ata (Post 385197) Hi I think sum local is absolute summation of continuty error in all CVs at present time step. global is summation of continuty error in all CVs at present time stem and cumulative is summation of global continuity errors from the first time step.
but does this error has any influence on my results? I think the answer is: No, It doesn't.

 alberto October 6, 2012 20:44

Yes, it does :D

The solver reports the error for informative purposes, as a measure of how good your solution is. You want this error to be as close to machine precision as possible.

Quote:
 Originally Posted by alberto (Post 385245) Yes, it does :D The solver reports the error for informative purposes, as a measure of how good your solution is. You want this error to be as close to machine precision as possible.
thank you Alberto,

but what do you think about the source of below error:
Code:

```DICPCG:  Solving for p, Initial residual = 1, Final residual = 6.72375e-08, No Iterations 62 time step continuity errors : sum local = 4.77002e+25, global = -9.93552e+15, cumulative = -9.93552e+15 Model mode 1 #0  Foam::error::printStack(Foam::Ostream&) in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libOpenFOAM.so" #1  Foam::sigFpe::sigHandler(int) in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libOpenFOAM.so" #2  Uninterpreted: #3  Foam::PBiCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libOpenFOAM.so" #4  Foam::fvMatrix<Foam::SymmTensor<double> >::solve(Foam::dictionary const&) in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so" #5  Foam::fvMatrix<Foam::SymmTensor<double> >::solve() in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so" #6  Foam::Giesekus::correct() in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so" #7  Foam::multiMode::correct() in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so" #8  Foam::viscoelasticModel::correct() in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/lib/libviscoelasticTransportModels.so" #9   in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/bin/BuoyantBoussinesqViscoelasticFluidFoam" #10  __libc_start_main in "/lib/i386-linux-gnu/libc.so.6" #11   in "/home/mostafa/OpenFOAM/OpenFOAM-2.1.0/platforms/linuxGccDPOpt/bin/BuoyantBoussinesqViscoelasticFluidFoam" Floating point exception```
my solver is the viscoelasticFluidFoam that I made some changes to it for solving natural convection. when I ran it, after some iterate the above error appeared.

anyone is here can help me????

thanks.

 ata October 8, 2012 05:23

Hi
If I want to speak general your schemes and/or methods for solving system of linear equations and/or their adjustments are improper.

Quote:
 Originally Posted by ata (Post 385469) Hi If I want to speak general your schemes and/or methods for solving system of linear equations and/or their adjustments are improper.
hi ata,.
can you tell me the details? I'm about two weeks that staying behind this error.

thank you.

 EricKl. September 12, 2013 15:24

Hello, I am trying to simulate a runoff, but I'm having the following problem:
What can I do?
Thanks

Code:

```/*---------------------------------------------------------------------------*\ | =========                |                                                | | \\      /  F ield        | OpenFOAM Extend Project: Open source CFD        | |  \\    /  O peration    | Version:  1.6-ext                              | |  \\  /    A nd          | Web:      www.extend-project.de                | |    \\/    M anipulation  |                                                | \*---------------------------------------------------------------------------*/ Build  : 1.6-ext-e61a8f0a3194 Exec  : viscoelasticInterFoam Date  : Sep 12 2013 Time  : 16:23:40 Host  : administrador-desktop PID    : 10189 Case  : /home/administrador/tutorials/viscoelastic/VIFErick/Escoamento nProcs : 1 SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE). // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Create time Create mesh for time = 0 // using new solver syntax: U {     solver          PBiCG;     preconditioner     {         preconditioner  DILU;     }     minIter        0;     maxIter        1000;     tolerance      1e-06;     relTol          0; } // using new solver syntax: taufirst {     solver          BiCGStab;     preconditioner     {         preconditioner  Cholesky;     }     minIter        0;     maxIter        1000;     tolerance      1e-06;     relTol          0; } // using new solver syntax: tau {     solver          BiCGStab;     preconditioner     {         preconditioner  Cholesky;     }     minIter        0;     maxIter        1000;     tolerance      1e-06;     relTol          0; } Reading g Reading transportProperties Reading field pd Reading field alpha Reading field U Reading/calculating face flux field phi Calculating field g.h Selecting viscoelastic model Giesekus time step continuity errors : sum local = 6.31081e-07, global = -6.31081e-07, cumulative = -6.31081e-07 --> FOAM FATAL ERROR: Continuity error cannot be removed by adjusting the outflow. Please check the velocity boundary conditions and/or run potentialFoam to initialise the outflow. Specified mass inflow  : 7.65133e-08 Specified mass outflow  : 0 Difference              : 7.65133e-08 Adjustable mass outflow : 0     From function adjustPhi (     surfaceScalarField& phi,     const volVectorField& U,     const volScalarField& p )     in file cfdTools/general/adjustPhi/adjustPhi.C at line 141. FOAM exiting```

 Bernhard September 13, 2013 02:39

Please check the velocity boundary conditions. What are the velocity boundary conditions in your case?

 EricKl. September 13, 2013 10:53

Hi,

My code for velocity is:

Code:

```/*--------------------------------*- C++ -*----------------------------------*\ | =========                |                                                | | \\      /  F ield        | OpenFOAM Extend Project: Open Source CFD        | |  \\    /  O peration    | Version:  1.6-ext                              | |  \\  /    A nd          | Web:      www.extend-project.de                | |    \\/    M anipulation  |                                                | \*---------------------------------------------------------------------------*/ FoamFile {     version    2.0;     format      ascii;     class      volVectorField;     object      U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions      [0 1 -1 0 0 0 0]; internalField  uniform (0 0 0); boundaryField {     inlet     {         type            fixedValue;         value          uniform (0.01868 0 0);     }     fixedWalls     {         type            fixedValue;         value          uniform (0 0 0);     }     frontAndBack     {         type            empty;     }     outlet     {         type            zeroGradient;     }     simetry     {         type            symmetryPlane;     }     atmosphere     {         type            pressureInletOutletVelocity;         phi            phi;         value          uniform (0 0 0);     }   } // ************************************************************************* //```

When I run potentialFoam, the program gives me

Code:

```/*---------------------------------------------------------------------------*\ | =========                |                                                | | \\      /  F ield        | OpenFOAM Extend Project: Open source CFD        | |  \\    /  O peration    | Version:  1.6-ext                              | |  \\  /    A nd          | Web:      www.extend-project.de                | |    \\/    M anipulation  |                                                | \*---------------------------------------------------------------------------*/ Build  : 1.6-ext-e61a8f0a3194 Exec  : potentialFoam Date  : Sep 13 2013 Time  : 11:55:07 Host  : administrador-desktop PID    : 16452 Case  : /home/administrador/tutorials/viscoelastic/VIFErick/Escoamento nProcs : 1 SigFpe : Enabling floating point exception trapping (FOAM_SIGFPE). // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // Create time Create mesh for time = 0 // using new solver syntax: U {     solver          PBiCG;     preconditioner     {         preconditioner  DILU;     }     minIter        0;     maxIter        1000;     tolerance      1e-06;     relTol          0; } // using new solver syntax: taufirst {     solver          BiCGStab;     preconditioner     {         preconditioner  Cholesky;     }     minIter        0;     maxIter        1000;     tolerance      1e-06;     relTol          0; } // using new solver syntax: tau {     solver          BiCGStab;     preconditioner     {         preconditioner  Cholesky;     }     minIter        0;     maxIter        1000;     tolerance      1e-06;     relTol          0; } Reading field p Reading field U --> FOAM FATAL IO ERROR: keyword SIMPLE is undefined in dictionary "/home/administrador/tutorials/viscoelastic/VIFErick/Escoamento/system/fvSolution" file: /home/administrador/tutorials/viscoelastic/VIFErick/Escoamento/system/fvSolution at line 21.     From function dictionary::subDict(const word& keyword) const     in file db/dictionary/dictionary.C at line 457. FOAM exiting```
I tried move and ajust velocity, but the errors continues
I'm really lost
:)

 All times are GMT -4. The time now is 16:42.