[Fool]

Hello together,

I am trying to do a hexahedral mesh of a basin with an inclination on one side.
My problem is that the edges at the top of the basin don't get cut off properly as you can see in the picture.

I've tried to play around with the edge refinement and some angle settings but nothing really worked well as I don't want that edge to be very fine because then it takes to long to run the process.
Do you have any suggestions for me?

Here's the snappyHexMeshDict. The part is named as "end_wall". The top of the geometry is "outlet".

PHP 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;   
snap            true;   
addLayers       false;   


geometry
{
    inlet.stl {type triSurfaceMesh; name inlet;}
    outlet.stl {type triSurfaceMesh; name outlet;}
    visc_main_wall.stl {type triSurfaceMesh; name visc_main_wall;}
    end_wall.stl {type triSurfaceMesh; name end_wall;}
  rinne_wall.stl {type triSurfaceMesh; name rinne_wall;}
    becken.stl {type triSurfaceMesh; name becken;}
    refinementBox {type searchableBox; min (-30 -23 -25); max ( 97 70 28);}
};

castellatedMeshControls
{
    maxLocalCells 1000000; 
    maxGlobalCells 2000000; 
    minRefinementCells 10;  
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 1;  

    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    features 
    (
        {file "inlet.eMesh"; level 3;} 
        {file "outlet.eMesh"; level 3;} 
        {file "visc_main_wall.eMesh"; level 3;} 
        {file "end_wall.eMesh"; level 3;} 
        {file "rinne_wall.eMesh"; level 3;} 
    );

 


    refinementSurfaces
    {
        inlet {level (2 2);}
        outlet {level (2 2);}
        visc_main_wall {level (3 3);} 
        end_wall {level (5 7);} 
        rinne_wall {level (5 5);} 
    }  


    resolveFeatureAngle 30;  
    refinementRegions       
    {volume {mode distance; levels ((0.0006 4) (0.002 3) (0.01 2));}} 
    locationInMesh (18.0 17.0 0.47);
    allowFreeStandingZoneFaces true;
}


snapControls
{
    nSmoothPatch 3;
    tolerance 4.0;
    nSolveIter 30;
    nRelaxIter 5;
    nFeatureSnapIter 15; 
    

implicitFeatureSnap false; 
explicitFeatureSnap true;
multiRegionFeatureSnap false; 

}



addLayersControls
{
    relativeSizes false;
    layers
    {
      visc_main_wall
             {nSurfaceLayers 3;} 
       end_wall 
          {nSurfaceLayers 3;} 
       rinne_wall
          {nSurfaceLayers 3;} 
    }

    expansionRatio 1.3;
    finalLayerThickness 0.00016; 
    minThickness 0.00008; 
    nGrow 0; 



    featureAngle 80; 
    nRelaxIter 3;  
    nSmoothSurfaceNormals 1; 
    nSmoothNormals 3; 
    nSmoothThickness 10;  
    maxFaceThicknessRatio 0.5; 
    maxThicknessToMedialRatio 0.3; 
    minMedianAxisAngle 130; 
    nBufferCellsNoExtrude 0;  
    nLayerIter 50; 
}




meshQualityControls
{
    maxNonOrtho 65;
    maxBoundarySkewness 20;
    maxInternalSkewness 4;
    maxConcave 80;
    minFlatness 0.5;
    minVol 1e-13;
    minTetQuality 1e-9;
    minArea -1;
    minTwist 0.02;
    minDeterminant 0.001;
    minFaceWeight 0.02;
    minVolRatio 0.01;
    minTriangleTwist -1;



    nSmoothScale 4;
    errorReduction 0.75;
}



debug 0;



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


mesh_end.jpg

[Fool]

By the way it does the same even worse at my inlet as you can see in the picture.

inlet.JPG

Below I post a picture of the .stl so you can see how it should look.

becken.jpg

[ssa_cfd]

I think your blockMesh is too coarse.

[Fool]

Okay. I'll try to do it with a finer blockmesh. But isn't there another possibility if I don't want a very fine mesh?

[guin]

Originally Posted by Fool

Okay. I'll try to do it with a finer blockmesh. But isn't there another possibility if I don't want a very fine mesh?

I guess that you want to extract the edge features... this post can be helpful https://www.cfd-online.com/Forums/op...tml#post312645