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-   -   Undefined keyword in dictionary in snappyHexMesh (http://www.cfd-online.com/Forums/openfoam-meshing-snappyhexmesh/109560-undefined-keyword-dictionary-snappyhexmesh.html)

RebeccaWS November 20, 2012 17:25

Undefined keyword in dictionary in snappyHexMesh
 
Hi

I've been trying to generate a mesh for an internal flow problem. I have successfully generate the background mesh in blockMesh and extracted edges, but when I ran snappyHexMesh from the case directory I got the following error message:

Code:

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
  Create time
 
  Create mesh for time = 0
 
  Read mesh in = 0.05 s
  --> FOAM Warning :
      From function entry::getKeyword(keyType&, Istream&)
      in file db/dictionary/entry/entryIO.C at line 77
      Reading /home/RWS/FlowrateCheck/10micronpore/system/snappyHexMeshDict
      found on line 31 the label 10
      expected either } or EOF
 
 
  --> FOAM FATAL IO ERROR:
  keyword castellatedMeshControls is undefined in dictionary "/home/RWS/FlowrateCheck/10micronpore/system/snappyHexMeshDict"
 
  file: /home/RWS/FlowrateCheck/10micronpore/system/snappyHexMeshDict from line 19 to line 34.
 
      From function dictionary::subDict(const word& keyword)
      in file db/dictionary/dictionary.C at line 479.
 
  FOAM exiting

I doublechecked my snappyHexMeshDict (please see below) but castellatedMeshControls is definitely defined in the code. Would someone be able to give me a pointer as to what I might be missing/doing wrong?

Many thanks

Reb

** My snappyHexMeshDict file **

Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  2.0.0                                |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/

FoamFile
{
    version    2.0;
    format      ascii;
    class      dictionary;
    object      snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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

// 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
{
    10micronpore_custom_ascii.stl
    {
        type triSurfaceMesh;
        name flowdomain;
    }
};

// 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 100000;

    // 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 3000000;

    // 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 20;

    // 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 2;

    // Explicit feature edge refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    // Specifies a level for any cell intersected by its edges.
    features
    (
        {
            file "10micronpore_custom_ascii.eMesh";
            level 0;
        }
    );

    // 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
    {
        "flowdomain_*"
          {
            level (8 9);    // Surface-wise min and max refinement level
          }
    }

    // Resolve sharp angles
    resolveFeatureAngle 180;

    // 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
    {
    }

    // 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 (0.002 0.0 0.0);

    // Whether any faceZones (as specified in the refinementSurfaces)
    // are only on the boundary of corresponding cellZones or also allow
    // free-standing zone faces. Not used if there are no faceZones.
    allowFreeStandingZoneFaces true;
}

// 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 10;

    //- Maximum number of snapping relaxation iterations. Should stop
    //  before upon reaching a correct mesh.
    nRelaxIter 10;

    //- Highly experimental and wip: number of feature edge snapping
    //  iterations. Leave out altogether to disable.
    //  Do not use here since mesh resolution too low and baffles present
    nFeatureSnapIter 10;
}

/*// 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
    {
        "flowdomain_*"
        {
          nSurfaceLayers 4;
        }
    }

    // Expansion factor for layer mesh
    expansionRatio 1.0;

    //- Wanted thickness of final added cell layer. If multiple layers
    //  is the
    //  thickness of the layer furthest away from the wall.
    //  Relative to undistorted size of cell outside layer.
    //  is the thickness of the layer furthest away from the wall.
    //  See relativeSizes parameter.
    finalLayerThickness 0.5;

    //- 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 0.1;

    //- 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.
    // Note: changed(corrected) w.r.t 17x! (didn't do anything in 17x)
    nGrow 0;

    // Advanced settings

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

    //- Maximum number of snapping relaxation iterations. Should stop
    //  before upon reaching a correct mesh.
    nRelaxIter 5;

    // Number of smoothing iterations of surface normals
    nSmoothSurfaceNormals 1;

    // Number of smoothing iterations of interior mesh movement direction
    nSmoothNormals 3;

    // Smooth layer thickness over surface patches
    nSmoothThickness 10;

    // 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
    // Note: changed(corrected) w.r.t 17x! 90 degrees corresponds to 130 in 17x.
    minMedianAxisAngle 90;


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


    // Overall max number of layer addition iterations. The mesher will exit
    // if it reaches this number of iterations; possibly with an illegal
    // mesh.
    nLayerIter 50;
}*/

// 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 3.5;
    maxInternalSkewness 2.5;

    //- 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 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-30;

    //- Minimum quality of the tet formed by the face-centre
    //  and variable base point minimum decomposition triangles and
    //  the cell centre. This has to be a positive number for tracking
    //  to work. Set to very negative number (e.g. -1E30) to
    //  disable.
    //    <0 = inside out tet,
    //      0 = flat tet
    //      1 = regular tet
    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 0.001;

    //- 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 4;
    //- 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;

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


RebeccaWS November 26, 2012 01:14

Still having the same problem.
 
Hi

I still haven't been able to solve the problem. Confusing thing is that the I can't find anything I might have done wrong (syntax mistake, typos etc) in the lines mentioned in the error message (i.e. lines 19-34) in my blockMeshDict file, which are:

Code:

castellatedMesh true;  snap            true;
  addLayers      false;    // For now
 
  // 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
  {
      10micronpore_custom_ascii.stl
      {
          type triSurfaceMesh;
          name flowdomain;

Also, the particular bit of code doesn't seem to be directly related to the keyword castellatedMeshControls being undefined. Coud someone please help??

Many thanks in advance

Rebecca

onyir November 26, 2012 03:09

Hi Rebecca. I think the problem is having the stl file name starting with a number, instead of a letter.

Regards,

Ricardo.

reza1980 April 28, 2013 09:39

I have same problem ,If some body has soloution please let me know

edalmau May 14, 2013 15:38

I didn't try to run SHM without some parameters on the castellated mesh, but you have MaxLocalCells & MaxLoadUnbalance with "//" at the beggining, they aren't recognized so maybe the snappyhexmesh didn't allow to mesh without it.

DanAndrea87 October 3, 2013 21:18

Hi everybody,
I had the same problem. After same tries I've solved it by adding a box (see the following code) just before "10micronpore_custom_ascii.stl".
It should looks like this:
Code:

geometry
{
    externalBox
    {
        type searchableBox;
        min (-0.3 -0.3 -0.4);
        max (0.3 0.3 0.4);
    }
    10micronpore_custom_ascii.stl
    {

etc...

So you have to create a box containing your entire geometry. That was the good news.
The bad news is that now I've another error:
Code:

--> FOAM FATAL IO ERROR:
keyword scale is undefined in dictionary "/home/REDUCED_TRIGA_core/system/snappyHexMeshDict.geometry.polyMesh.regions"

file: /home/REDUCED_TRIGA_core/system/snappyHexMeshDict.geometry.polyMesh.regions from line 41 to line 77.

    From function dictionary::lookupEntry(const word&, bool, bool) const
    in file db/dictionary/dictionary.C at line 402.

FOAM exiting

Does someone have a solution?


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