Utility snappyHexMesh refines background mesh in direction to the surface model, reading set-up from system/snappyHexMeshDict:

castellatedMesh true;
snap            true;
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
{
    StatorAMI1.stl { type triSurfaceMesh; name StatorAMI1; }
    StatorAMI2.stl { type triSurfaceMesh; name StatorAMI2; }
    StatorBlade.stl { type triSurfaceMesh; name StatorBlade; }
    StatorShroud.stl { type triSurfaceMesh; name StatorShroud; }
    StatorHub.stl { type triSurfaceMesh; name StatorHub; }
    StatorIn.stl { type triSurfaceMesh; name StatorIn; }

    StatorMXP_00.stl { type triSurfaceMesh; name StatorMXP00; }
    StatorMXP_01.stl { type triSurfaceMesh; name StatorMXP01; }
    StatorMXP_02.stl { type triSurfaceMesh; name StatorMXP02; }
    StatorMXP_03.stl { type triSurfaceMesh; name StatorMXP03; }
    StatorMXP_04.stl { type triSurfaceMesh; name StatorMXP04; }
    StatorMXP_05.stl { type triSurfaceMesh; name StatorMXP05; }
    StatorMXP_06.stl { type triSurfaceMesh; name StatorMXP06; }
    StatorMXP_07.stl { type triSurfaceMesh; name StatorMXP07; }
    StatorMXP_08.stl { type triSurfaceMesh; name StatorMXP08; }
    StatorMXP_09.stl { type triSurfaceMesh; name StatorMXP09; }
    StatorMXP_10.stl { type triSurfaceMesh; name StatorMXP10; }
    StatorMXP_11.stl { type triSurfaceMesh; name StatorMXP11; }
    StatorMXP_12.stl { type triSurfaceMesh; name StatorMXP12; }
    StatorMXP_13.stl { type triSurfaceMesh; name StatorMXP13; }
    StatorMXP_14.stl { type triSurfaceMesh; name StatorMXP14; }
    StatorMXP_15.stl { type triSurfaceMesh; name StatorMXP15; }
    StatorMXP_16.stl { type triSurfaceMesh; name StatorMXP16; }
    StatorMXP_17.stl { type triSurfaceMesh; name StatorMXP17; }
    StatorMXP_18.stl { type triSurfaceMesh; name StatorMXP18; }
    StatorMXP_19.stl { type triSurfaceMesh; name StatorMXP19; }
    StatorMXP_20.stl { type triSurfaceMesh; name StatorMXP20; }
    StatorMXP_21.stl { type triSurfaceMesh; name StatorMXP21; }
    StatorMXP_22.stl { type triSurfaceMesh; name StatorMXP22; }
    StatorMXP_23.stl { type triSurfaceMesh; name StatorMXP23; }
    StatorMXP_24.stl { type triSurfaceMesh; name StatorMXP24; }
    StatorMXP_25.stl { type triSurfaceMesh; name StatorMXP25; }
    StatorMXP_26.stl { type triSurfaceMesh; name StatorMXP26; }
    StatorMXP_27.stl { type triSurfaceMesh; name StatorMXP27; }
    StatorMXP_28.stl { type triSurfaceMesh; name StatorMXP28; }
    StatorMXP_29.stl { type triSurfaceMesh; name StatorMXP29; }
    StatorMXP_30.stl { type triSurfaceMesh; name StatorMXP30; }
    StatorMXP_31.stl { type triSurfaceMesh; name StatorMXP31; }
    StatorMXP_32.stl { type triSurfaceMesh; name StatorMXP32; }
    StatorMXP_33.stl { type triSurfaceMesh; name StatorMXP33; }
    StatorMXP_34.stl { type triSurfaceMesh; name StatorMXP34; }
    StatorMXP_35.stl { type triSurfaceMesh; name StatorMXP35; }
};



// 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 10000000;

    // 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 0; // 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. // This is a featureEdgeMesh, read from constant/triSurface for now. features ( // { // file "stator_features.eMesh"; // level 0; // } { file "StatorAMI1.eMesh"; level 0; } { file "StatorAMI2.eMesh"; level 0; } { file "StatorBlade.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
    {
        "(StatorShroud|StatorHub)"
        {
            level (3 3);
        }
        "StatorIn"
        {
            level (1 3);
        }
        "StatorBlade"
        {
            level (3 4);
        }
        "StatorAMI.*"
        {
            level (3 3);
        }
        "StatorMXP.*"
        {
            level (4 4);
        }
    }

    // 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
    {
        
    }


    // 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 (-0.07 0.05 0.6);


    // 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;
}

Create the mesh running snappyHexMesh utility:

 snappyHexMesh

Renumber mesh using renumberMesh utility:

 renumberMesh -latestTime

When finished, check the mesh running checkMesh and view the mesh in paraview:

 checkMesh
 paraFoam