[winghey]

not sure where to begin. i'm quite new to this. i want to create the simplest wind tunnel, with a simple object (say a square, 2d) in it, and get the pressure on different points on it's surface. i went through major parts of the guide. it was quite overwhelming so i tried combining two examples - the lid driven cavity and a wing one (https://www.openfoam.com/documentati...irfoil-2d.html)
i debugged for a long time and right now got stuck with

Time = 1

smoothSolver:  Solving for Ux, Initial residual = 1, Final residual = 9.00995e-06, No Iterations 103
#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::sigFpe::sigHandler(int) at ??:?
#2  ? in /lib64/libc.so.6
#3  Foam::DICPreconditioner::calcReciprocalD(Foam::Field<double>&, Foam::lduMatrix const&) at ??:?
#4  Foam::DICPreconditioner::DICPreconditioner(Foam::lduMatrix::solver const&, Foam::dictionary const&) at ??:?
#5  Foam::lduMatrix::preconditioner::addsymMatrixConstructorToTable<Foam::DICPreconditioner>::New(Foam::lduMatrix::solver const&, Foam::dictionary const&) at ??:?
#6  Foam::lduMatrix::preconditioner::New(Foam::lduMatrix::solver const&, Foam::dictionary const&) at ??:?
#7  Foam::PCG::scalarSolve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#8  Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#9  Foam::fvMatrix<double>::solveSegregated(Foam::dictionary const&) at ??:?
#10  Foam::fvMatrix<double>::solveSegregatedOrCoupled(Foam::dictionary const&) at ??:?
#11  Foam::fvMesh::solve(Foam::fvMatrix<double>&, Foam::dictionary const&) const at ??:?
#12  ? at ??:?
#13  __libc_start_main in /lib64/libc.so.6
#14  ? at ??:?

my questions are:
1. why are the lines of errors not shown? makes debugging quite impossible
2. what is my best option to make progress? is there a simpler example file that corresponds to my problem? is it legitimate to upload the whole case file and ask for help debugging?

thank you.

[Carlo_P]

Hey John,

starts with OpenFOAM is not easy.
The lines say the the Ux calculation performs quite good and some problem occurs with Uy.
Also Ux seems to converge not so nice, since it used 100 iteratios, when normally it need only 3-5.


The best thing you can bo is upload the BCs from the 0 folder and make a checkMesh, in order to understand if the mesh is good or not.


Her you can find an example for wath you are looking for:


https://www.cfdsupport.com/download-...hmed-body.html


another tutorial can be find also in:
OpenFOAM\OpenFOAM-dev\tutorials\incompressible\simpleFoam\motorBike


ATTENTION, THE TUTORIALS ARE ONLY EXAMPLES. MAYBE THE SETUP IS NOT THE BEST ONE.

[yambanshee]

The error messages are very difficult to interpret. Based on what you posted, my thinking is in your solver settings within fvSolution.

My recommendation would be to share your checkMesh results, boundary condition files, and fvSchemes and fvSolution files here. It should then be possible to narrow down the problem

[winghey]

hi both. first of all thank you. i'll look into the the other examples you offered.
as for checkmesh, here's the results. i also attached the config files (the whole set up actually, just in case).

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1906                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : v1906 OPENFOAM=1906
Arch   : "LSB;label=32;scalar=64"
Exec   : checkMesh
Date   : Aug 07 2019
Time   : 14:39:25
Host   : 049e7a89f1bf
PID    : 615
I/O    : uncollated
Case   : /home/ofuser/workingDir/Projects/HyperWing/foam/test
nProcs : 1
trapFpe: Floating point exception trapping enabled (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

Time = 0

Mesh stats
    points:           3370
    internal points:  0
    faces:            6486
    internal faces:   3120
    cells:            1601
    faces per cell:   6
    boundary patches: 5
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     1601
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
 ***Total number of faces on empty patches is not divisible by the number of cells in the mesh. Hence this mesh is not 1D or 2D.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
   *Number of regions: 2
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "0/cellToRegion"
  <<Writing region 0 with 1 cells to cellSet region0
  <<Writing region 1 with 1600 cells to cellSet region1

Checking patch topology for multiply connected surfaces...
    Patch               Faces    Points   Surface topology                  
    inlet               40       82       ok (non-closed singly connected)  
    outlet              40       82       ok (non-closed singly connected)  
    fixedWalls          4        8        ok (non-closed singly connected)  
    frontAndBack        2        8        ok (non-closed singly connected)  
    defaultFaces        3280     3362     ok (non-closed singly connected)  

Checking faceZone topology for multiply connected surfaces...
    No faceZones found.

Checking basic cellZone addressing...
    No cellZones found.

Checking geometry...
    Overall domain bounding box (-1 -1 0) (2 2 0.01)
    Mesh has 1 geometric (non-empty/wedge) directions (1 0 0)
    Mesh has 1 solution (non-empty) directions (1 0 0)
    All edges aligned with or perpendicular to non-empty directions.
    Boundary openness (-2.50973e-19 -2.50973e-19 6.17632e-17) OK.
    Max cell openness = 1.54198e-16 OK.
    Max aspect ratio = 1 OK.
    Minimum face area = 0.00075. Maximum face area = 0.01.  Face area magnitudes OK.
    Min volume = 5.625e-05. Max volume = 0.0001.  Total volume = 0.0901.  Cell volumes OK.
    Mesh non-orthogonality Max: 0 average: 0
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 2.13821e-14 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End