[CfdUser5855]

Hi all,

This should be an easy one, but I can't seem to fix it.

My mesh is created no problem, passes mesh checks etc. But as seen in the attached photo, it refines far too high up the domain.

I've tried changing refinement region, changing to mode distance, changing the levels etc but it always creates the same mesh.

Can anyone please advise how I can lower where the refinement starts? The domain is 250 m tall, and I ideally want the nearest 50 m to the surface refined and the rest is alright.

Below is my snappyhexmesh:

castellatedMesh true;
snap true;
addLayers true;

geometry
{
refinementBox
{
type searchableBox;
min (1635 518305 0);
max (2700 519270 200);
}

DuneField
{
type triSurfaceMesh;
file "DuneField.stl";
}
};



castellatedMeshControls
{

maxLocalCells 2000000000;

maxGlobalCells 2000000000;

minRefinementCells 1;

maxLoadUnbalance 0.10;

nCellsBetweenLevels 1;


refinementSurfaces
{
DuneField
{
// Surface-wise min and max refinement level
level (0 0);

// Optional region-wise level specification

regions
{
refinementBox
{
level (5 5);
}
}

}
}

resolveFeatureAngle 5;

refinementRegions
{

refinementBox
{
mode inside;
levels ((5 5)); //4 4 or 6 6
}

}


locationInMesh (2000 518500 250);

allowFreeStandingZoneFaces true;
}




snapControls
{
nSmoothPatch 3;

tolerance 2.0;

nSolveIter 30;

nRelaxIter 5;
}




addLayersControls
{

relativeSizes true;

layers
{
}

expansionRatio 1.0;

finalLayerThickness 0.3;

minThickness 0.25;

nGrow 0;

featureAngle 60;

nRelaxIter 5;

nSmoothSurfaceNormals 1;

nSmoothNormals 3;

nSmoothThickness 10;

maxFaceThicknessRatio 0.5;

maxThicknessToMedialRatio 0.3;

minMedianAxisAngle 90;

nBufferCellsNoExtrude 0;

nLayerIter 50;

nRelaxedIter 20;
}


meshQualityControls
{
maxNonOrtho 45;
maxBoundarySkewness 10;
maxInternalSkewness 2;
maxConcave 80;
minVol 1e-13;

minTetQuality 1e-30;

minArea -1;

minTwist 0.05;

minDeterminant 0.001;

minFaceWeight 0.05;

minVolRatio 0.01;

minTriangleTwist -1;

relaxed
{
maxNonOrtho 45;
}
}

mergeTolerance 1e-5;



Thanks