ENH: balancing before refinement

[OpenFOAM-1.6.x.git] / tutorials / incompressible / simpleFoam / motorBike / system / snappyHexMeshDict

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  1.6                                   |
|   \\  /    A nd           | Web:      http://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       true;


// 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
{
    motorBike.stl
    {
        type triSurfaceMesh;
        name motorBike;
    }

    refinementBox
    {
        type searchableBox;
        min (-1.0 -0.7 0.0);
        max ( 8.0  0.7 2.5);
    }
};



// 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 1000000;

    // 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 2000000;

    // 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 10;

    // 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 3;



    // 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
    (
        //{
        //    file "someLine.eMesh";
        //    level 2;
        //}
    );



    // 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
    {
        motorBike
        {
            // Surface-wise min and max refinement level
            level (5 6);
        }
    }

    // Resolve sharp angles
    resolveFeatureAngle 30;


    // 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 ((1E15 4));
        }
    }


    // 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 (3 3 0.43);
}



// Settings for the snapping.
snapControls
{
    //- Number of patch smoothing iterations before finding correspondence
    //  to surface
    nSmoothPatch 3;

    //- 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 30;

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



// 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
    {
        minZ
        {
            nSurfaceLayers 1;
        }
        motorBike_frt-fairing:001%1
        {
            nSurfaceLayers 1;
        }
        motorBike_windshield:002%2
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-rim:005%5
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-rim:010%10
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-wh-rim:011%11
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-wh-brake-disk:012%12
        {
            nSurfaceLayers 1;
        }
        motorBike_frame:016-shadow%13
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-susp:014%14
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-susp:014-shadow%15
        {
            nSurfaceLayers 1;
        }
        motorBike_frame:016%16
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-rim:005-shadow%17
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-chain-hub:022%22
        {
            nSurfaceLayers 1;
        }
        motorBike_rearseat%24
        {
            nSurfaceLayers 1;
        }
        motorBike_frt-fairing%25
        {
            nSurfaceLayers 1;
        }
        motorBike_windshield%26
        {
            nSurfaceLayers 1;
        }
        motorBike_headlights%27
        {
            nSurfaceLayers 1;
        }
        motorBike_driversseat%28
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-body%29
        {
            nSurfaceLayers 1;
        }
        motorBike_fuel-tank%30
        {
            nSurfaceLayers 1;
        }
        motorBike_exhaust%31
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-rim%32
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-mud-guard%33
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-wh-rim%34
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-wh-brake-disk%35
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-brake-caliper%36
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-wh-tyre%37
        {
            nSurfaceLayers 1;
        }
        motorBike_hbars%38
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-forks%39
        {
            nSurfaceLayers 1;
        }
        motorBike_chain%40
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-tyre%41
        {
            nSurfaceLayers 1;
        }
        motorBike_square-dial%42
        {
            nSurfaceLayers 1;
        }
        motorBike_round-dial%43
        {
            nSurfaceLayers 1;
        }
        motorBike_dial-holder%44
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-susp%45
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-brake-lights%46
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-light-bracket%47
        {
            nSurfaceLayers 1;
        }
        motorBike_frame%48
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-mud-guard%49
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-susp-spring-damp%50
        {
            nSurfaceLayers 1;
        }
        motorBike_fairing-inner-plate%51
        {
            nSurfaceLayers 1;
        }
        motorBike_clutch-housing%52
        {
            nSurfaceLayers 1;
        }
        motorBike_radiator%53
        {
            nSurfaceLayers 1;
        }
        motorBike_water-pipe%54
        {
            nSurfaceLayers 1;
        }
        motorBike_water-pump%55
        {
            nSurfaceLayers 1;
        }
        motorBike_engine%56
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-shock-link%57
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-brake-fluid-pot-bracket%58
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-brake-fluid-pot%59
        {
            nSurfaceLayers 1;
        }
        motorBike_footpeg%60
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-chain-hub%61
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-brake-caliper%62
        {
            nSurfaceLayers 1;
        }
        motorBike_rider-helmet%65
        {
            nSurfaceLayers 1;
        }
        motorBike_rider-visor%66
        {
            nSurfaceLayers 1;
        }
        motorBike_rider-boots%67
        {
            nSurfaceLayers 1;
        }
        motorBike_rider-gloves%68
        {
            nSurfaceLayers 1;
        }
        motorBike_rider-body%69
        {
            nSurfaceLayers 1;
        }
        motorBike_frame:0%70
        {
            nSurfaceLayers 1;
        }
        motorBike_frt-fairing:001-shadow%74
        {
            nSurfaceLayers 1;
        }
        motorBike_windshield-shadow%75
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-mud-guard-shadow%81
        {
            nSurfaceLayers 1;
        }
        motorBike_fr-wh-brake-disk-shadow%83
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-mud-guard-shadow%84
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-susp-spring-damp-shadow%85
        {
            nSurfaceLayers 1;
        }
        motorBike_radiator-shadow%86
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-shock-link-shadow%87
        {
            nSurfaceLayers 1;
        }
        motorBike_rear-brake-fluid-pot-bracket-shadow%88
        {
            nSurfaceLayers 1;
        }
        motorBike_rr-wh-chain-hub-shadow%89
        {
            nSurfaceLayers 1;
        }
    }

    // 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.
    //  See relativeSizes parameter.
    finalLayerThickness 0.3;

    //- 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.
    nGrow 1;


    // Advanced settings

    //- When not to extrude surface. 0 is flat surface, 90 is when two faces
    //  make straight angle.
    featureAngle 30;

    //- Maximum number of snapping relaxation iterations. Should stop
    //  before upon reaching a correct mesh.
    nRelaxIter 3;

    // 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
    minMedianAxisAngle 130;

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

    // Overall max number of layer addition iterations
    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 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;

    //- 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;


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