[Pj.]

The following 2 dictionaries get successfully executed by OF 2.2.1

***HEADER REMOVED TO SHORTEN THE MESSAGE***
FoamFile 
{ 
    version     2.0; 
    format      ascii; 
    class       dictionary; 
    object      blockMeshDict; 
} 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 

X1    -18650; //-35000.0000;
X2    15000.0000;

Y1    -1500.0000;
Y2    1500.0000;

Z1      0.0000;
Z2    2000.0000;
Z3    4000.0000;

vertices
(
    ($X1    $Y1    $Z1)    //0
    ($X2    $Y1    $Z1)    //1
    ($X1    $Y2    $Z1)    //2
    ($X2    $Y2    $Z1)    //3
    ($X1    $Y1    $Z2)    //4
    ($X2    $Y1    $Z2)    //5
    ($X1    $Y2    $Z2)    //6
    ($X2    $Y2    $Z2)    //7
    ($X1    $Y1    $Z3)    //8
    ($X2    $Y1    $Z3)    //9
    ($X1    $Y2    $Z3)    //10
    ($X2    $Y2    $Z3)    //11
);

blocks
(
    hex (0 1 3 2 4 5 7 6)
    (126 13 6)
    simpleGrading    (1.00 1.00 20.00)

    hex (4 5 7 6 8 9 11 10)
    (126 13 6)
    simpleGrading    (1.00 1.00 0.10)

);

edges
(
);

patches
(
    patch // KIND: patch, simmetryPlane, wall... 
    FRONT
    (
        (0 4 6 2)
        (4 8 10 6)
    )

    patch // KIND: patch, simmetryPlane, wall... 
    BACK
    (
        (3 7 5 1)
        (7 11 9 5)
    )

    patch // KIND: patch, simmetryPlane, wall... 
    RIGHT
    (
        (0 1 5 4)
        (4 5 9 8)
    )

    patch // KIND: patch, simmetryPlane, wall... 
    LEFT
    (
        (3 2 6 7)
        (7 6 10 11)
    )

    patch // KIND: patch, simmetryPlane, wall... 
    BOT
    (
        (0 1 3 2)
    )

    patch // KIND: patch, simmetryPlane, wall... 
    TOP
    (
        (8 9 11 10)
    )

);

mergePatchPairs
(
);

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.7.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
// NOTE: LARGE NUMBER OF ITERATIONS VERSION!

// Which of the steps to run
castellatedMesh true;
snap            false; 
addLayers       false;  


// Geometry. Definition of all surfaces. All surfaces are of class
// searchableSurface.
// Surfaces are used
// - to specify refinement for any mesh cell intersecting it
// - to specify refinement for any mesh cell inside/outside/near
// - to 'snap' the mesh boundary to the surface
geometry
{
    refinementBox
    {
        type searchableBox;
        min (-10000 -1500 0); //(-2   -1.5 0);
        max (15000 1500 4000); //( 3.5  1.5 0.7);
    }
    refinementBox2
    {
        type searchableBox;
        min (0 -1500 0); //(-2   -1.5 0);
        max (15000 1500 4000); //( 3.5  1.5 0.7);
    }
};



// Settings for the castellatedMesh generation.
castellatedMeshControls
{

    // Refinement parameters
    // ~~~~~~~~~~~~~~~~~~~~~

    // If local number of cells is >= maxLocalCells on any processor
    // switches from from refinement followed by balancing
    // (current method) to (weighted) balancing before refinement.
    maxLocalCells 500000000;

    // Overall cell limit (approximately). Refinement will stop immediately
    // upon reaching this number so a refinement level might not complete.
    // Note that this is the number of cells before removing the part which
    // is not 'visible' from the keepPoint. The final number of cells might
    // actually be a lot less.
    maxGlobalCells 800000000;

    // The surface refinement loop might spend lots of iterations refining just a
    // few cells. This setting will cause refinement to stop if <= minimumRefine
    // are selected for refinement. Note: it will at least do one iteration
    // (unless the number of cells to refine is 0)
    minRefinementCells 1000;

    // Allow a certain level of imbalance during refining
    // (since balancing is quite expensive)
    // Expressed as fraction of perfect balance (= overall number of cells /
    // nProcs). 0=balance always.
    maxLoadUnbalance 0.10;


    // Number of buffer layers between different levels.
    // 1 means normal 2:1 refinement restriction, larger means slower
    // refinement.
    nCellsBetweenLevels 15;



    // Explicit feature edge refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    // Specifies a level for any cell intersected by its edges.
    // This is a featureEdgeMesh, read from constant/triSurface for now.
    features
    (
    );



    // Surface based refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~

    // Specifies two levels for every surface. The first is the minimum level,
    // every cell intersecting a surface gets refined up to the minimum level.
    // The second level is the maximum level. Cells that 'see' multiple
    // intersections where the intersections make an
    // angle > resolveFeatureAngle get refined up to the maximum level.

    refinementSurfaces
    {
    }

    // Resolve sharp angles
    resolveFeatureAngle 30; //90;


    // Region-wise refinement
    // ~~~~~~~~~~~~~~~~~~~~~~

    // Specifies refinement level for cells in relation to a surface. One of
    // three modes
    // - distance. 'levels' specifies per distance to the surface the
    //   wanted refinement level. The distances need to be specified in
    //   descending order.
    // - inside. 'levels' is only one entry and only the level is used. All
    //   cells inside the surface get refined up to the level. The surface
    //   needs to be closed for this to be possible.
    // - outside. Same but cells outside.

    refinementRegions
    {
        refinementBox
        {
            mode inside;
            levels ((1.0 1));
        }

        refinementBox2
        {
            mode inside;
            levels ((1.0 2));
        }
    }


    // Mesh selection
    // ~~~~~~~~~~~~~~

    // After refinement patches get added for all refinementSurfaces and
    // all cells intersecting the surfaces get put into these patches. The
    // section reachable from the locationInMesh is kept.
    // NOTE: This point should never be on a face, always inside a cell, even
    // after refinement.
    locationInMesh (0 0 1000);
    
    allowFreeStandingZoneFaces false;
}



// Settings for the snapping.
snapControls
{
    //- Number of patch smoothing iterations before finding correspondence
    //  to surface
    nSmoothPatch 10;

    //- Relative distance for points to be attracted by surface feature point
    //  or edge. True distance is this factor times local
    //  maximum edge length.
    tolerance 4.0;

    //- Number of mesh displacement relaxation iterations.
    nSolveIter 200;

    //- Maximum number of snapping relaxation iterations. Should stop
    //  before upon reaching a correct mesh.
    nRelaxIter 40;
    
    // Feature snapping

        //- Number of feature edge snapping iterations.
        //  Leave out altogether to disable.
        nFeatureSnapIter 10;

        //- Detect (geometric) features by sampling the surface
        implicitFeatureSnap false;

        //- Use castellatedMeshControls::features
        explicitFeatureSnap true;

        //- Detect features between multiple surfaces
        //  (only for explicitFeatureSnap, default = false)
        multiRegionFeatureSnap true;
}



// Settings for the layer addition.
addLayersControls
{
    // Are the thickness parameters below relative to the undistorted
    // size of the refined cell outside layer (true) or absolute sizes (false).
    relativeSizes true;

    // Per final patch (so not geometry!) the layer information
    layers
    {
    }

    // Expansion factor for layer mesh
    expansionRatio 1.2;

    //- Wanted thickness of final added cell layer. If multiple layers
    //  is the thickness of the layer furthest away from the wall.
    //  See relativeSizes parameter.
    finalLayerThickness 0.8;

    //- Minimum thickness of cell layer. If for any reason layer
    //  cannot be above minThickness do not add layer.
    //  Relative to undistorted size of cell outside layer.
    minThickness 0.0000000001; //0.001;

    //- If points get not extruded do nGrow layers of connected faces that are
    //  also not grown. This helps convergence of the layer addition process
    //  close to features.
    nGrow 0; //5;


    // Advanced settings

    //- When not to extrude surface. 0 is flat surface, 90 is when two faces
    //  make straight angle.
    featureAngle 130;

    //- Maximum number of snapping relaxation iterations. Should stop
    //  before upon reaching a correct mesh.
    nRelaxIter 40;

    // Number of smoothing iterations of surface normals
    nSmoothSurfaceNormals 20;

    // Number of smoothing iterations of interior mesh movement direction
    nSmoothNormals 30;

    // Smooth layer thickness over surface patches
    nSmoothThickness 20;

    // Stop layer growth on highly warped cells
    maxFaceThicknessRatio 0.5;

    // Reduce layer growth where ratio thickness to medial
    // distance is large
    maxThicknessToMedialRatio 0.3;

    // Angle used to pick up medial axis points
    minMedianAxisAngle 90;

    // Create buffer region for new layer terminations
    nBufferCellsNoExtrude 0;

    // Overall max number of layer addition iterations
    nLayerIter 300;
}



// Generic mesh quality settings. At any undoable phase these determine
// where to undo.
meshQualityControls
{
    //- Maximum non-orthogonality allowed. Set to 180 to disable.
    maxNonOrtho 65;

    //- Max skewness allowed. Set to <0 to disable.
    maxBoundarySkewness 20;
    maxInternalSkewness 4;

    //- Max concaveness allowed. Is angle (in degrees) below which concavity
    //  is allowed. 0 is straight face, <0 would be convex face.
    //  Set to 180 to disable.
    maxConcave 80;

    //- Minimum projected area v.s. actual area. Set to -1 to disable.
    minFlatness 0.5;

    //- Minimum pyramid volume. Is absolute volume of cell pyramid.
    //  Set to a sensible fraction of the smallest cell volume expected.
    //  Set to very negative number (e.g. -1E30) to disable.
    minVol 1e-13;
    minTetQuality 1e-30;


    //- Minimum face area. Set to <0 to disable.
    minArea -1;

    //- Minimum face twist. Set to <-1 to disable. dot product of face normal
    //- and face centre triangles normal
    minTwist 0.02;

    //- minimum normalised cell determinant
    //- 1 = hex, <= 0 = folded or flattened illegal cell
    minDeterminant 0.00001;

    //- minFaceWeight (0 -> 0.5)
    minFaceWeight 0.02;

    //- minVolRatio (0 -> 1)
    minVolRatio 0.01;

    //must be >0 for Fluent compatibility
    minTriangleTwist -1;


    // Advanced

    //- Number of error distribution iterations
    nSmoothScale 30;
    //- amount to scale back displacement at error points
    errorReduction 0.75;
}


// Advanced

// Flags for optional output
// 0 : only write final meshes
// 1 : write intermediate meshes
// 2 : write volScalarField with cellLevel for postprocessing
// 4 : write current intersections as .obj files
debug 0;


// Merge tolerance. Is fraction of overall bounding box of initial mesh.
// Note: the write tolerance needs to be higher than this.
mergeTolerance 1E-6;


// ************************************************************************* //

but, if I run them using OF 2.3.0

/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.3.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 2.3.0-f5222ca19ce6
Exec   : snappyHexMesh
Date   : Sep 03 2014
Time   : 14:13:46
Host   : "Blow04"
PID    : 16893
Case   : /home/pol/LUCA/mapping_WtSliceSmall/spectrumRecovery
nProcs : 1
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

Read mesh in = 0.17 s

Overall mesh bounding box  : (-18650 -1500 0) (15000 1500 4000)
Relative tolerance         : 1e-06
Absolute matching distance : 0.0340194

Reading refinement surfaces.
Read refinement surfaces in = 0 s

Reading refinement shells.
Refinement level 1 for all cells inside refinementBox
Refinement level 2 for all cells inside refinementBox2
Read refinement shells in = 0 s

Setting refinement level of surface to be consistent with shells.
Checked shell refinement in = 0 s

Reading features.
Read features in = 0 s


Determining initial surface intersections
-----------------------------------------

Edge intersection testing:
    Number of edges             : 62274
    Number of edges to retest   : 62274
    Number of intersected edges : 0
Calculated surface intersections in = 0.15 s

Initial mesh : cells:19656  faces:62274  points:23114
Cells per refinement level:
    0    19656

Adding patches for surface regions
----------------------------------

Patch Type                Region                        
----- ----                ------                        
Added patches in = 0 s

Selecting decompositionMethod none
Layer thickness specified as final layer and expansion ratio.

Refinement phase
----------------

Found point (0 0 1000) in cell 7377 on processor 0

Surface refinement iteration 0
------------------------------

Marked for refinement due to surface intersection          : 0 cells.
Determined cells to refine in = 0.02 s
Selected for refinement : 0 cells (out of 19656)
Stopping refining since too few cells selected.


Removing mesh beyond surface intersections
------------------------------------------

Found point (0 0 1000) in global region 0 out of 1 regions.
Keeping all cells in region 0 containing point (0 0 1000)
Selected for keeping : 19656 cells.
Edge intersection testing:
    Number of edges             : 62274
    Number of edges to retest   : 0
    Number of intersected edges : 0

Shell refinement iteration 0
----------------------------

Marked for refinement due to distance to explicit features : 0 cells.
Marked for refinement due to refinement shells             : 14664 cells.
Determined cells to refine in = 0.08 s
Selected for internal refinement : 14664 cells (out of 19656)
Edge intersection testing:
    Number of edges             : 377736
    Number of edges to retest   : 362453
    Number of intersected edges : 0
Refined mesh in = 0.94 s
After refinement shell refinement iteration 0 : cells:122304  faces:377736  points:133399
Cells per refinement level:
    0    4992
    1    117312

Shell refinement iteration 1
----------------------------

Marked for refinement due to distance to explicit features : 0 cells.
Marked for refinement due to refinement shells             : 69888 cells.
Determined cells to refine in = 0.05 s
Selected for internal refinement : 69888 cells (out of 122304)
Edge intersection testing:
    Number of edges             : 1864056
    Number of edges to retest   : 1704130
    Number of intersected edges : 0
Refined mesh in = 4.8 s
After refinement shell refinement iteration 1 : cells:611520  faces:1864056  points:641449
Cells per refinement level:
    0    4992
    1    47424
    2    559104

Shell refinement iteration 2
----------------------------

Marked for refinement due to distance to explicit features : 0 cells.
Marked for refinement due to refinement shells             : 0 cells.
Determined cells to refine in = 0.2 s
Selected for internal refinement : 0 cells (out of 611520)
Stopping refining since too few cells selected.


Dangling coarse cells refinement iteration 0
--------------------------------------------

Determined cells to refine in = 0.04 s
Selected for refinement : 0 cells (out of 611520)
Stopping refining since too few cells selected.


Dangling coarse cells refinement iteration 0
--------------------------------------------

Determined cells to refine in = 0.03 s
Selected for refinement : 0 cells (out of 611520)
Stopping refining since too few cells selected.


Splitting mesh at surface intersections
---------------------------------------

Introducing baffles for 0 faces that are intersected by the surface.

Edge intersection testing:
    Number of edges             : 1864056
    Number of edges to retest   : 0
    Number of intersected edges : 0
Created baffles in = 1.87 s


After introducing baffles : cells:611520  faces:1864056  points:641449
Cells per refinement level:
    0    4992
    1    47424
    2    559104

Introducing baffles to block off problem cells
----------------------------------------------

#0  Foam::error::printStack(Foam::Ostream&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1  Foam::sigSegv::sigHandler(int) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2   in "/lib/x86_64-linux-gnu/libc.so.6"
#3  Foam::List<int>::List(int, int const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/snappyHexMesh"
#4  Foam::meshRefinement::nearestPatch(Foam::List<int> const&) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#5  Foam::meshRefinement::markFacesOnProblemCells(Foam::dictionary const&, bool, Foam::Field<double> const&, Foam::List<int> const&) const in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#6  Foam::meshRefinement::handleSnapProblems(Foam::snapParameters const&, bool, bool, Foam::Field<double> const&, Foam::dictionary const&, Foam::Time&, Foam::List<int> const&, Foam::List<int> const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#7  Foam::meshRefinement::baffleAndSplitMesh(bool, Foam::snapParameters const&, bool, bool, Foam::Field<double> const&, bool, double, Foam::dictionary const&, Foam::Time&, Foam::List<int> const&, Foam::List<int> const&, Foam::Vector<double> const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#8  Foam::autoRefineDriver::baffleAndSplitMesh(Foam::refinementParameters const&, Foam::snapParameters const&, bool, Foam::dictionary const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#9  Foam::autoRefineDriver::doRefine(Foam::dictionary const&, Foam::refinementParameters const&, Foam::snapParameters const&, bool, Foam::dictionary const&) in "/opt/openfoam230/platforms/linux64GccDPOpt/lib/libautoMesh.so"
#10  
 in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/snappyHexMesh"
#11  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#12  
 in "/opt/openfoam230/platforms/linux64GccDPOpt/bin/snappyHexMesh"
Segmentation fault (core dumped)

Is this a bug? Or did I make a mistake somewhere?

[wyldckat]

Greetings Luca,

If I've recognised properly the error, it is a bug in OpenFOAM 2.3.0. I accompanied a similar case here on the forum and respective bug fix sometime ago.... let me see if I can find them... oh, wait, I didn't accompany the bug fix itself, but I might have found the actual bug report+fix:

• The thread where this was originally discussed: http://www.cfd-online.com/Forums/ope...-crashing.html
  • The associated bug report, which did not result in a solution: http://www.openfoam.org/mantisbt/view.php?id=1264
• The bug report that seems to have resulted in a bug fix: http://www.openfoam.org/mantisbt/view.php?id=1303

After looking at these bug reports and thread, and having a better look at the dictionary files you provided, it is possible that you could work around the problem. But on the other hand, it also seems like you've trigger yet another bug.


Right now I don't have enough time to check this myself, but I'll leave a note on my to-do list to into this during the weekend.
In the meantime:

• If you can build OpenFOAM 2.3.x from source code, then you might be able to no longer trigger this bug.
• Or you can try and double-check if there is any problem with the refinement boxes, which might not be picking up all of the correct cells from the base mesh. In other words, try increasing or reducing the sizes of the refinement boxes.
  I say this because it is possible that the refinement boxes are picking up different cells from the base mesh in each OpenFOAM version you've used, which would explain why it crashes with one version, but not the other one.
• Run checkMesh will all of the verifications:
  

  checkMesh -allTopology -allGeometry

  after you've run blockMesh. If there are any flaws on the mesh, this would explain the crash.

Best regards,
Bruno

[Pj.]

Thanks Bruno.

I already workaround-ed the error switching to Openfoam 2.2.1. As you can see the mesh is REALLY simple and I don't expect a difference between 2.3.0 and 2.2.1.

I just wanted to understand if this is a bug and report it with the dictionaries that trigger it.

Tell me if I should report it somewhere and/or provide more informations.

Best regards,
Luca

[wyldckat]

Hi Luca,

I've tested this just now and the problem is already fixed in OpenFOAM 2.3.x.
You'll need to build 2.3.x from source code: http://www.openfoam.org/download/git.php

Best regards,
Bruno