CFD Online Discussion Forums - [cfMesh] layer addiction on sharp edges

Hi all,

I’m facing some big issues about layer addiction with cfMesh on sharp edges.
My geometry is quite simple; what is challenging me, they are the two 45° pipes inside the domain.
As you may see by enclosed links, pipes are cut and sharp edges are present; small blu lines are skewFaces: skewness > 4.4

As you may see by following meshDict

Code:

SurfaceFile "regionAirAmb.fms";



maxCellSize 0.002;  



//minCellSize 0.001;

//boundaryCellSize 0.002; 



/*

edgeMeshRefinement

{



        edgeMesh1

        {

                edgeFile        "edgeAmb1.vtk"; //sharp edges

                cellSize 0.001;

        }

        

}*/





/*

localRefinement 

{

    interAirSolido2 //near sharps edges

    {

        cellSize 0.001;

//                refinementThickness  0.001;

    }

    interAirSolido3 //near sharps edges

    {

        cellSize 0.001;

//                refinementThickness  0.001;

    }

    interAirSolido4 //near sharps edges

    {

        cellSize 0.0005;

//                refinementThickness  0.001;

    }



}*/



boundaryLayers

{



        patchBoundaryLayers

        {

                "interAirSolido.*"

                {        

                        nLayers 5;

                        thicknessRatio 1.2;

                //        maxFirstLayerThickness  0.004;

                //        alllowDiscontinuity                1;

                }

                wallAirAmb

                {        

                        nLayers 5;

                        thicknessRatio 1.2;

                //        maxFirstLayerThickness  0.004;

                //        alllowDiscontinuity                1;

                }



        }

}

I’ve tried many combinations of the meshDict to get rid of skewness and nonOrthogonality on the faces at the sharp edges.

What I can say is:

- distance between cut pipe and domain is approximately 2mm
- if I set 2mm for minCellSize or boundaryCellSize, with nr.3 layers I can get a poor good mesh;
- If I use increaseMeshQuality, with nr.3 layers I can get rid of problem faces, but layers are not so many

then

- if I increase the refinement up to 5e-4mm and 3 layers, I get a mesh with more skewFaces and nonOrthogoanlFaces.

Then

If I use 2mm for minCellSize or boundaryCellSize, with layers > 3 skewness and nonOrthogonality increase

If with both of the upper settings I use increaseMeshQuality, I can’t get rid of the problem faces.

So, the question is simple, what should I do?

I meshed the stl by using Salome and all surface checks are positive.
I also tried to increase the resolution of the cells on the problem edges, but no effects.

What should I do?

https://www.dropbox.com/s/blh0mc2zcrsrt86/stl.PNG?dl=0
https://www.dropbox.com/s/bhf00sq08z...eshed.PNG?dl=0
https://www.dropbox.com/s/bgdxhgwt70...Faces.PNG?dl=0
https://www.dropbox.com/s/blh0mc2zcrsrt86/stl.PNG?dl=0

stl file of the domain:

https://www.dropbox.com/s/kzkr3w1ubd...irAmb.zip?dl=0