CFD Online Discussion Forums - need help with conjugate heat transfer

Quote:
Originally Posted by skuznet (Post 475747)
Thank you for your reply. Can you give me idea how can it do it - create conformal mesh. Can I do it in HelyxOS?
my snappyHexMeshDict:
Code:
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| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |

|  \\    /   O peration     | Version:  2.2.0                                 |

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|    \\/     M anipulation  |                                                 |

\*---------------------------------------------------------------------------*/

FoamFile

{

    version     2.0;

    format      ascii;

    class       dictionary;

    object      autoHexMeshDict;

}



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



// Which of the steps to run

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

{

    coolant.stl

    {

        type triSurfaceMesh;

        name coolant;

    }



    engine.stl

      {

            type triSurfaceMesh;

            name engine;

      }



    air.stl

      {

        type triSurfaceMesh;

        name air;

      }

};







// 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;



    // 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 "coolant.eMesh";

            level 0;

            //levels ((0 2)(1.5 1)(3 0));

        }



        {

          file "engine.eMesh";

          level 0;        

        }



        {

          file "air.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

    {

        coolant

        {

          // Surface-wise min and max refinement level

          level (0 2);



          faceZone coolant;

          cellZone coolant;

          cellZoneInside inside;

        }



        engine

          {

            level (0 2);

            faceZone engine;

            cellZone engine;

            cellZoneInside inside;

          }

        air

          {

            level (0 2);

            faceZone air;

            cellZone air;

            cellZoneInside inside;

          }

       

    }



    // 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 (0.001 -12.501 0.001);

    //locationInMesh (0.1 0.1 0.1);



    // 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 false;

}







// 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 1.0;



    //- Number of mesh displacement relaxation iterations.

    nSolveIter 30;



    //- Maximum number of snapping relaxation iterations. Should stop

    //  before upon reaching a correct mesh.

    nRelaxIter 5;



    //- Highly experimental and wip: number of feature edge snapping

    //  iterations. Leave out altogether to disable.

    //  Of limited use in this case since faceZone faces not handled.

    nFeatureSnapIter 10;



    explicitFeatureSnap true;

    implicitFeatureSnap false;

    multiRegionFeatureSnap true;

}







// Settings for the layer addition.

addLayersControls

{

    relativeSizes true;



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

    layers

    {

        maxY

        {

            nSurfaceLayers 3;

        }

    }



    // Expansion factor for layer mesh

    expansionRatio 1.3;



    // 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.

    finalLayerThickness 1;



    // 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

    // are perpendicular

    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 2;



    // Stop layer growth on highly warped cells

    maxFaceThicknessRatio 0.5;



    // Reduce layer growth where ratio thickness to medial

    // distance is large

    maxThicknessToMedialRatio 1;



    // 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 80;



    //- 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 pyramid volume. Is absolute volume of cell pyramid.

    //  Set to very negative number (e.g. -1E30) to disable.

    minVol 0;



    //- Minimum quality of the tet formed by the face-centre

    //  and variable base point minimum decomposition triangles and

    //  the cell centre.  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;





// ************************************************************************* //
I have highlighted the interesting parts in red, you can rename those *.stl accordingly. Once the mesh is properly created, you can use
Code:
splitMeshRegions -cellZones -overwrite
to split the mesh into individual regions.

Good luck!