[rocketLauncher]

Hi all,

After a lot of experimenting, I am managing to get a rather good mesh with snappy. I am having some trouble with the boundary layer at certain points however. The BL will be constructed well and the start degrading before it's completely interrupted.

I attach some pictures to demonstrate the issue and my snappyHexMeshDict. Thank you in advance.

/*--------------------------------*- 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
castellatedMesh true;
snap            true;
addLayers       true;


geometry
{
    inlet1.stl
    {
	name	inlet1;
	type	triSurfaceMesh;
    }       

    inlet2.stl
    {
	name	inlet2;
	type	triSurfaceMesh;
    }    

    outlet.stl
    {
	name	outlet;
	type	triSurfaceMesh;
    }    

    symmetry_plane.stl
    {
	name	symmetry_plane;
	type	triSurfaceMesh;
    }    

    walls.stl
    {
	name	walls;
	type	triSurfaceMesh;
    }    
}

// Settings for the castellatedMesh generation.
castellatedMeshControls
{
    // Refinement parameters
    // ~~~~~~~~~~~~~~~~~~~~~

    maxLocalCells 500000;
    maxGlobalCells 6000000;
    minRefinementCells 10;
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 3;

    // Explicit feature edge refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    features
    (

       {
            file    "inlet1.eMesh";
            level   4;
       }

       {
            file    "inlet2.eMesh";
            level   4;
       }

       {
            file    "outlet.eMesh";
            level   4;
       }

       {
            file    "symmetry_plane.eMesh";
            level   4;
       }

       {
            file    "walls.eMesh";
            level   4;
       }
    );

    // Surface based refinement
    // ~~~~~~~~~~~~~~~~~~~~~~~~
     refinementSurfaces
    {
	inlet1
	{
		level	(4 4);
		patchInfo
		{
			type	patch;
		}
	}

	inlet2
	{
		level	(4 4);
		patchInfo
		{
			type	patch;
		}
	}

	outlet
	{
		level	(4 4);
		patchInfo
		{
			type	patch;
		}
	}

	symmetry_plane
	{
		level	(4 4);
		patchInfo
		{
			type	symmetry;
			inGroups (symmetry);
		}
	}

	walls
	{
		level	(5 5);
		patchInfo
		{
			type	wall;
			inGroups (walls);
		}
	}     
    }

    // Resolve sharp angles
    resolveFeatureAngle 30;
    //planarAngle 30;

    // Region-wise refinement
    // ~~~~~~~~~~~~~~~~~~~~~~
    refinementRegions
    {
        // Define any refinement regions here if needed
		
    };

    // Mesh selection
    // ~~~~~~~~~~~~~~
    locationInMesh (0.01937 0.01 0.023);
    allowFreeStandingZoneFaces true;
}

// Settings for the snapping.
snapControls
{
    nSmoothPatch 3;
    tolerance 4.0;
    nSolveIter 0;
    nRelaxIter 5;

    // Feature snapping
    nFeatureSnapIter 10;
    implicitFeatureSnap false;
    explicitFeatureSnap true;
    multiRegionFeatureSnap false;
}

// Settings for the layer addition.
addLayersControls
{
    relativeSizes true;

    layers
    {
        walls
        {
            nSurfaceLayers 10;
        }
    }

    expansionRatio 1.1;
    finalLayerThickness 0.1;
    minThickness 0.01;
    nGrow 0;
    featureAngle 5;
    slipFeatureAngle 5;
    nRelaxIter 3;
    nSmoothSurfaceNormals 1;
    nSmoothNormals 3;
    nSmoothThickness 10;
    maxFaceThicknessRatio 0.5;
    maxThicknessToMedialRatio 0.3;
    minMedialAxisAngle 90;
    nBufferCellsNoExtrude 0;
    nLayerIter 50;
}

// Generic mesh quality settings. At any undoable phase these determine
// where to undo.
meshQualityControls
{
    maxNonOrtho 65;
    maxBoundarySkewness 20;
    maxInternalSkewness 4;
    maxConcave 80;
    minVol 1e-13;
    minTetQuality 1e-30;
    minArea -1;
    minTwist 0.02;
    minDeterminant 0.001;
    minFaceWeight 0.02;
    minVolRatio 0.01;
    minTriangleTwist -1;

    // Advanced
    nSmoothScale 4;
    errorReduction 0.75;
}

// Advanced

// Flags for optional output
debug 0;

// Merge tolerance. Is fraction of overall bounding box of initial mesh.
mergeTolerance 1e-6;

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