CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Meshing & Mesh Conversion

[snappyHexMesh] snappyHexMesh for Intersecting surfaces

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   June 14, 2016, 06:38
Default snappyHexMesh for Intersecting surfaces
  #1
New Member
 
Anamitra Bagchi
Join Date: Mar 2015
Posts: 4
Rep Power: 7
Anamitra is on a distinguished road
Hello everyone!!

I am trying to mesh two intersecting surfaces in snappyhexMesh.

Issue: I have two stl surfaces, stl1 and stl2. Both are close and sometimes intersecting. I would like to have both as separate patches and would also need a finer mesh around them. However, as I do understand that it might be bit difficult.

I tried with 'inside' - refinement box, 'distance' - from the surfaces ( which I didn't expect to work anyway).

Hence my question is,
-Are there other options which I might use?
-or is there any other meshing software which might help, and can also export the mesh to openfoam format later.

Please let me know if I should add some more info.

Code:
/*--------------------------------*- 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;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //


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
{

	stl1.stl {type triSurfaceMesh; name stl1;}
	stl2.stl {type triSurfaceMesh; name stl2;}
	refinementBox 
        {
 	type searchableBox; 
        min (-3 -1 16.65); 
        max (15 4 18.95);
	}

//	refinementBox2 {type searchableBox; min ( -6 -85); max ( 10 3 -6);}

};

castellatedMeshControls
{
    maxLocalCells 2500000;  //max cells per CPU core
    maxGlobalCells 20000000; //max cells to use before mesh deletion step
    minRefinementCells 0;  //was 0 - zero means no bad cells are allowed during stages
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 4;  // 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 "inlet.eMesh"; level 0;} // add STL files if needed
        {file "stl1.eMesh"; level 2;} 
	{file "stl2.eMesh"; level 2;} 
    );

    // Surface based refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~

    refinementSurfaces // Surface-wise min and max refinement level
    {
	stl1 {level (4 5);} 
	stl2 {level (3 4);} 
    }
  


    resolveFeatureAngle 60;  // Resolve sharp angles // Default 30
    refinementRegions        // In descending levels of fine-ness
    {


         stl2 { mode distance; levels ((0.008 5)); }
//       refinementBox2 { mode inside; levels ((1.0 5)); }
    }
    locationInMesh (5.235 6.235 17.235);  
//to decide which side of mesh to keep **
    allowFreeStandingZoneFaces true;
}


// Settings for the snapping.
snapControls
{
    nSmoothPatch 3;
    tolerance 2.0;
    nSolveIter 60;
    nRelaxIter 15;
    nFeatureSnapIter 15; // default is 10
    
// 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;
// deafault is false - detects features between multiple surfaces

}

// Settings for the layer addition.

addLayersControls 

//add the PATCH names from inside the STL file so STLpatchName_insideSTLName 

{
    relativeSizes true; // was true
    layers
    {
//	jetwall {nSurfaceLayers 4;} // was 3
    }

    expansionRatio 1.0;
    finalLayerThickness 0.03; //was 0.00016
    minThickness 0.00008; //was 0.0008
    nGrow 1; // was 1 


    // Advanced settings

    featureAngle 80; 
// was 70 //- When not to extrude surface. 0 is flat, 90 is right angle.
    nRelaxIter 3;  
//- Max# of snapping relaxation iter. Should stop before upon reaching a correct mesh.
    nSmoothSurfaceNormals 1;  
// Number of smoothing iterations of surface normals
    nSmoothNormals 3;
// Number of smoothing iterations of interior mesh movement direction
    nSmoothThickness 10;  
// Smooth layer thickness over surface patches
    maxFaceThicknessRatio 0.5; 
// Stop layer growth on highly warped cells
    maxThicknessToMedialRatio 0.3; 
// Reduce layer growth where ratio thickness to medial distance is large
    minMedianAxisAngle 130; 
// Angle used to pick up medial axis points
    nBufferCellsNoExtrude 0;   
// Create buffer region for new layer terminations
    nLayerIter 50; 
// Overall max number of layer addition iterations
}

// Generic mesh quality settings. At any undoable phase these determine
// where to undo.

meshQualityControls
{
    maxNonOrtho 65;
    maxBoundarySkewness 20;
    maxInternalSkewness 4;
    maxConcave 80;
    minFlatness 0.5;
    minVol 1e-14;
    minTetQuality 1e-9;
    minArea -1;
    minTwist 0.02;
    minDeterminant 0.001;
    minFaceWeight 0.02;
    minVolRatio 0.01;
    minTriangleTwist -1;

    // Advanced

    nSmoothScale 4;
    errorReduction 0.75;
}

// Advanced

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-4;
Attached Images
File Type: jpg Scene_1.jpg (63.9 KB, 63 views)
Anamitra is offline   Reply With Quote

Reply

Tags
intersecting geometry, snappyhexmesh

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
[snappyHexMesh] snappyHexMesh not snappy on certain surfaces. Stevie_1200 OpenFOAM Meshing & Mesh Conversion 5 June 21, 2018 05:11
[snappyHexMesh] creating baffles using snappyHexMesh (for given random shaped surfaces) ashish.svm OpenFOAM Meshing & Mesh Conversion 1 January 17, 2018 02:24
[snappyHexMesh] MultiRegionMeshing with SnappyHexMesh - SplitMeshRegions doesnt pickup my surfaces Kenneth J. OpenFOAM Meshing & Mesh Conversion 0 January 30, 2015 11:07
[snappyHexMesh] snappyHexMesh not refining surfaces Hydro1004 OpenFOAM Meshing & Mesh Conversion 3 August 29, 2012 12:56
[snappyHexMesh] problemes modelling surfaces with snappyhexmesh gija79 OpenFOAM Meshing & Mesh Conversion 5 June 30, 2010 14:50


All times are GMT -4. The time now is 04:04.