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-   -   Wingtip vortex OpenFoam. Error solving with simpleFoam (https://www.cfd-online.com/Forums/openfoam-solving/201968-wingtip-vortex-openfoam-error-solving-simplefoam.html)

luram94 May 16, 2018 14:08
Wingtip vortex OpenFoam. Error solving with simpleFoam
 
Hi foamers.

I am simulating a wingtip vortex for a laminar, steady case.
I have adapted the Airfoil2D tutorial to my 3D case.
I am using a simulation type laminar that i've typed on the turbulenceProperties file.

My mesh is a wing of 0.1 chord enclosed on a prism. I've meshed it with PointWise.



I have checked the smallest cell of my mesh to adapt the deltaT for the courant number. The smallest cell size is "Minimum face area = 1.4231e-09". So I am trying different deltaT values but the error always happens on the same point.


Here you can see the mistake.


I hope someone could help me.
Thank you !!



luram94@Aspire-E5-574G:~/OpenFOAM/luram94-5.0/run/airFoil2D1$ simpleFoam
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5.x |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 5.x-197d9d3bf20a
Exec : simpleFoam
Date : May 16 2018
Time : 19:45:59
Host : "Aspire-E5-574G"
PID : 5766
I/O : uncollated
Case : /home/luram94/OpenFOAM/luram94-5.0/run/airFoil2D1
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

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

Create mesh for time = 0


SIMPLE: convergence criteria
field p tolerance 1e-05
field U tolerance 1e-05

Reading field p

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Selecting turbulence model type laminar
Selecting laminar stress model Stokes
No MRF models present

No finite volume options present


Starting time loop

Time = 0.0001

smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.0695286, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.0254532, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 1, Final residual = 0.0654825, No Iterations 4
GAMG: Solving for p, Initial residual = 1, Final residual = 0.0943924, No Iterations 16
time step continuity errors : sum local = 9.32871e-09, global = -1.09984e-20, cumulative = -1.09984e-20
ExecutionTime = 0.24 s ClockTime = 0 s

Time = 0.0002

smoothSolver: Solving for Ux, Initial residual = 0.417036, Final residual = 0.0237835, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 0.525095, Final residual = 0.0355146, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.361729, Final residual = 0.0187467, No Iterations 4
GAMG: Solving for p, Initial residual = 0.994142, Final residual = 0.0944352, No Iterations 4
time step continuity errors : sum local = 2.68322e-07, global = -6.64015e-21, cumulative = -1.76385e-20
ExecutionTime = 0.32 s ClockTime = 0 s

Time = 0.0003

smoothSolver: Solving for Ux, Initial residual = 0.48106, Final residual = 0.0291823, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 0.592922, Final residual = 0.0163415, No Iterations 6
smoothSolver: Solving for Uz, Initial residual = 0.365147, Final residual = 0.0195021, No Iterations 4
GAMG: Solving for p, Initial residual = 0.989267, Final residual = 0.098107, No Iterations 65
time step continuity errors : sum local = 6.09575e-06, global = -2.51469e-21, cumulative = -2.01532e-20
ExecutionTime = 0.61 s ClockTime = 0 s

Time = 0.0004

smoothSolver: Solving for Ux, Initial residual = 0.633188, Final residual = 0.0383804, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.631868, Final residual = 0.0342176, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.544371, Final residual = 0.0420833, No Iterations 2
GAMG: Solving for p, Initial residual = 0.99557, Final residual = 0.0985544, No Iterations 22
time step continuity errors : sum local = 0.000284088, global = -7.5344e-20, cumulative = -9.54973e-20
ExecutionTime = 0.74 s ClockTime = 0 s

Time = 0.0005

smoothSolver: Solving for Ux, Initial residual = 0.503184, Final residual = 0.0360833, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 0.600972, Final residual = 0.0378856, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.580002, Final residual = 0.0347582, No Iterations 4
GAMG: Solving for p, Initial residual = 0.999452, Final residual = 0.0939822, No Iterations 17
time step continuity errors : sum local = 0.00724173, global = 6.35417e-19, cumulative = 5.39919e-19
ExecutionTime = 0.86 s ClockTime = 0 s

Time = 0.0006

smoothSolver: Solving for Ux, Initial residual = 0.494103, Final residual = 0.013902, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 0.45221, Final residual = 0.0124333, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.506377, Final residual = 0.0317716, No Iterations 4
GAMG: Solving for p, Initial residual = 0.992318, Final residual = 0.0991528, No Iterations 21
time step continuity errors : sum local = 0.191447, global = 6.35768e-18, cumulative = 6.8976e-18
ExecutionTime = 1 s ClockTime = 1 s

Time = 0.0007

smoothSolver: Solving for Ux, Initial residual = 0.524298, Final residual = 0.0290546, No Iterations 6
smoothSolver: Solving for Uy, Initial residual = 0.525085, Final residual = 0.0402515, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.929924, Final residual = 0.0688259, No Iterations 10
GAMG: Solving for p, Initial residual = 0.999893, Final residual = 0.0971346, No Iterations 10
time step continuity errors : sum local = 29.8918, global = -5.18405e-15, cumulative = -5.17715e-15
ExecutionTime = 1.1 s ClockTime = 1 s

Time = 0.0008

smoothSolver: Solving for Ux, Initial residual = 0.549428, Final residual = 0.0525383, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.535445, Final residual = 0.00941288, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.485405, Final residual = 0.00742206, No Iterations 4
GAMG: Solving for p, Initial residual = 0.89532, Final residual = 0.0826279, No Iterations 3
time step continuity errors : sum local = 294.428, global = -6.74072e-14, cumulative = -7.25843e-14
ExecutionTime = 1.16 s ClockTime = 1 s

Time = 0.0009

smoothSolver: Solving for Ux, Initial residual = 0.538549, Final residual = 0.0375504, No Iterations 6
smoothSolver: Solving for Uy, Initial residual = 0.572799, Final residual = 0.0172758, No Iterations 8
smoothSolver: Solving for Uz, Initial residual = 0.47479, Final residual = 0.0266104, No Iterations 8
GAMG: Solving for p, Initial residual = 3.30709e-05, Final residual = 2.99641e-06, No Iterations 12
time step continuity errors : sum local = 7.49553e+06, global = 1.44336e-08, cumulative = 1.44335e-08
ExecutionTime = 1.27 s ClockTime = 1 s

Time = 0.001

smoothSolver: Solving for Ux, Initial residual = 0.466723, Final residual = 0.0230642, No Iterations 46
smoothSolver: Solving for Uy, Initial residual = 0.471586, Final residual = 0.0297526, No Iterations 42
smoothSolver: Solving for Uz, Initial residual = 0.37227, Final residual = 0.0159206, No Iterations 48
GAMG: Solving for p, Initial residual = 1, Final residual = 0.0966592, No Iterations 6
time step continuity errors : sum local = 4.40691e+16, global = -60.8033, cumulative = -60.8033
ExecutionTime = 1.42 s ClockTime = 1 s

Time = 0.0011

smoothSolver: Solving for Ux, Initial residual = 0.400004, Final residual = 177.261, No Iterations 1000
smoothSolver: Solving for Uy, Initial residual = 0.428658, Final residual = 285.171, No Iterations 1000
smoothSolver: Solving for Uz, Initial residual = 0.445417, Final residual = 649.365, No Iterations 1000
#0 Foam::error::printStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#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 at ??:?
#4 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMa trix::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 ??:?
#5 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#6 Foam::fvMatrix<double>::solveSegregated(Foam::dict ionary const&) at ??:?
#7 Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
#8 Foam::fvMatrix<double>::solve() at ??:?
#9 ? at ??:?
#10 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#11 ? at ??:?

klausb October 19, 2018 11:53
Hello,

it's usually worth to try a tolerance for p lower than that of the other values e.g.

Code:
solvers
{
    p
    {
        solver                PCG;
        preconditioner  FDIC;
        tolerance          1e-08;
        relTol                0;
    }

    U
    {
          solver                PBiCGStab;
          preconditioner  DILU;
          tolerance          1e-7;
          relTol                0.01;
    }
...
But actually to give real advice, you should provide more information about your mesh including the number of cells around your airfoil (try 300 cells chord wise) and the other mesh parameters used. Did you use checkMesh and renumberMesh? How many cells are there?

What's your AOA, reynolds number etc.?

Could you post your case or at least some key files including fvSolution, fvSchemes and controlDict?

The setup of the airFoil2D case appears rather "minimalistic" especially the fvSchemes.


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