[kewsinger]

Hi everyone,

i got a problem defining patches using SHM. I have a tube and a rotor in the tube. Both as STL. I end up having a "tube" and a "rotor" patch. What i need now is a separated inlet and an outlet patch (marked red in the image). And further i have to split the part of the mesh containing the rotor to let it rotate with cyclicAMI (marked yellow).

Can anybody tell me how to realize this case? If you need any further info, just let me know.

Thanks!
Mario

[kewsinger]

i add my snappyHexMeshDict:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.0                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

// Which of the steps to run; true/false to switch on/off
castellatedMesh true;   // make basic mesh?
snap            true;   // decide to snap back to surface?
addLayers       false;   // decide to add viscous layers?




geometry        //Load in STL files here and define patch names; refinement areas possible
{
    rotor.stl 
        {
            type triSurfaceMesh;        //The standard type “triSurfaceMesh” reads a copy of each surface on to each processor when running in parallel.
            name rotor;                 //defines the patch name for further use in the file
        } 
    ader.stl 
        {
            type triSurfaceMesh; 
            name ader;
        }
    stator_hohl.stl 
        {
            type triSurfaceMesh; 
            name stator_hohl;
        }
}




castellatedMeshControls         //Prescribe feature, surface and volume mesh refinements
{
    maxLocalCells 1000000;      //max cells per CPU core
    maxGlobalCells 2000000;     //max cells to use before mesh deletion step
    minRefinementCells 10;      //was 0 - zero means no bad cells are allowed during refinement stages
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 1;      // expansion factor between each high & low refinement zone

    //Explicit feature edge refinement
    features                    //taken from STL from each .eMesh file created by "SurfaceFeatureExtract" command
    (
        {file "rotor.eMesh"; level 1;} 
        {file "stator_hohl.eMesh"; level 1;}
        {file "ader.eMesh"; level 1;}
    );

    //Surface based refinement
    refinementSurfaces          //Surface-wise min and max refinement level
    {
    rotor {level (2 2);}
    stator_hohl {level (2 2);}
    ader {level (0 0);}
    }  

    resolveFeatureAngle 80;     //Resolve sharp angles; Default 30

    refinementRegions           //In descending levels of fine-ness
    {
        ader
        {
            mode distance;      //mode distance means 0.0006 meters from surface it will refine to level 4; others possible: "inside", "outside"
            levels ((0.001 1)); 
        }
    } 
    
    locationInMesh (-0.0028 -0.0050 0.0035);    //to decide which side of mesh to keep; very very important; pick a point in paraView inside the area you want to be meshed; vor rotor: (-0.0028 -0.0050 0.0035); innerhalb stator: (0.01 0.01 -0.007) 
    allowFreeStandingZoneFaces true;           //Whether to allow zone faces that share the same owner and neighbour cell zone. If kept these can cause quality issues when the zone faces are snapped to the surface
}




snapControls                    //Settings for the snapping; Control mesh surface snapping
{
    nSmoothPatch 3;             //Number of pre smoothing iterations of patch points before projection to the surface is performed
    tolerance 4.0;              //Scaling of the maximum edge length for attraction to the surface
    nSolveIter 30;              //Number of interior smoothing iterations applied to snapped displacement field
    nRelaxIter 5;               //Controls number of scaling back iterations for error reduction stage
    nFeatureSnapIter 15;        //default is 10; Number of feature snapping iterations to perform.
    
    // New settings from openfoam 2.2 onwards for SHMesh
    implicitFeatureSnap false;          //default is false - detects without doing surfaceFeatureExtract
    explicitFeatureSnap true;           //default is true
    multiRegionFeatureSnap false;       //default is false - detects features between multiple surfaces
}




addLayersControls                       //Control boundary layer mesh growth. Add the PATCH names from inside the STL file so STLpatchName_insideSTLName 
{
    layers
    {
    rotor
             {nSurfaceLayers 1;}     //Specification of the number of layers to be grown on each patch.
    }

    expansionRatio 1.3;                 //expansionRatio is the ratio of heights from one layer to the next consecutive layer in the direction away from the surface
    finalLayerThickness 0.00016;        //finalLayerThickness is the ratio of the final layer height relative to the adjacent surface mesh size
    minThickness 0.00008;               //Specification of a minimum layer thickness below which height layers will automatically be collapsed. 
    relativeSizes false;                //The final layer thickness and minimum thickness can be defined as either being relative (true) to the background spacing ΔS or defined as an absolute (false) length
    nGrow 0;                            //was 1 

    // Advanced settings
    featureAngle 80;                    //When not to extrude surface. 0 is flat, 90 is right angle.
    
    nRelaxIter 5;                       //Max# of snapping relaxation iter. Should stop before upon reaching a correct mesh.
    
    nSmoothSurfaceNormals 1;            //Number of smoothing iterations of surface normals; default=1
    nSmoothNormals 3;                   //Number of smoothing iterations of interior mesh movement direction; default=3
    nSmoothThickness 10;                //Smooth layer thickness over surface patches; default=10
    
    maxThicknessToMedialRatio 0.3;      //Reduce layer growth where ratio thickness to medial distance is large;  default=0.3
    minMedianAxisAngle 130;             //Angle used to pick up medial axis points
    
    maxFaceThicknessRatio 0.5;          //Stop layer growth on highly warped cells
    
    nBufferCellsNoExtrude 0;            //Create buffer region for new layer terminations
    
    nLayerIter 50;                      //Overall max number of layer addition iterations
}




meshQualityControls             //Generic mesh quality settings. At any undoable phase these determine where to undo.
{
    maxNonOrtho 65;             //default=65
    maxBoundarySkewness 20;     //default=20
    maxInternalSkewness 4;      //default=4
    maxConcave 80;              //default=80
    minFlatness 0.5; 
    minVol 1e-13;               //default=1e-13
    minTetQuality 1e-9;         //This metric needs to be set to a small positive value to guarantee an inside cell check works correctly for tracking routines e.g. streamlines 
    minArea -1e-13;             //default=1e-30
    minTwist 0.02;              //default=0.05
    minDeterminant 0.001;       //default=0.001
    minFaceWeight 0.02;         //default=0.05
    minVolRatio 0.01;           //default=0.01
    minTriangleTwist -1;        //default=-1

    // Advanced
    nSmoothScale 4;             //default=4
    errorReduction 0.75;        //default=0.75
}




// Advanced

debug 0;                //put to "1" if all meshes should be written, not only the final one

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


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

[kewsinger]

hi everyone,

okay now i figured how to get a inlet and outlet using "autoPatch".
But now i am stuck trying to get faces inside the tube for the rotor part. I suppose it works somehow using "createPatch" ? But i am really not sure if this is the right way. Do i even need a boundary there for letting the inner part rotate. Or do i have to split the mesh?
Some input would be nice, the tutorials aren't that clear to me :/

thanks!

[kewsinger]

nobody at least a little hint?