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-   -   blockMesh prism undefined faces (https://www.cfd-online.com/Forums/openfoam/76313-blockmesh-prism-undefined-faces.html)

flowris May 21, 2010 08:48

blockMesh prism undefined faces
 
Hello,

I am trying to create a mesh using blockMesh around a prismatic object. The mesh block under this object is triangular. According to the User Guide pp. U-139 paragraph 5.3.3, one can create this by collapsing vertices. This is what I did, and the mesh looks good.

I define the patches as you can see in the attachment. When running "blockMesh", I get the following warning:

Quote:

Default patch type set to empty
--> FOAM Warning :
From function polyMesh::polyMesh(... construct from shapes...)
in file meshes/polyMesh/polyMeshFromShapeMesh.C at line 576
Found 1 undefined faces in mesh; adding to default patch.
Indeed this gives an error when solving later. I cannot find the patch "empty" nor "defaultFaces" in my postprocessor (paraview 3.7), anyways.

Who knows what went wrong?

ngj May 21, 2010 09:47

You have forgotten the attachment.

Best regards,

Niels

flowris May 25, 2010 02:28

Thank you Niels, for making me aware of that. Uploading keeps on failing here, so this is a copy of my blockMeshDict file:


/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //



convertToMeters 1;

vertices
(
(-20 0 -4)
(-20 25 -4)
(-4 0 -4)
(-4 25 -4)
(0 1 -4)
(0 25 -4)
(4 0 -4)
(4 25 -4)
(50 0 -4)
(50 25 -4)

(-20 0 -1)
(-20 25 -1)
(-4 0 -1)
(-4 25 -1)
(0 1 -1)
(0 25 -1)
(4 0 -1)
(4 25 -1)
(50 0 -1)
(50 25 -1)

(-20 0 1)
(-20 25 1)
(-4 0 1)
(-4 25 1)
(0 1 1)
(0 25 1)
(4 0 1)
(4 25 1)
(50 0 1)
(50 25 1)
);

blocks
(
// Lower layer
hex (2 6 4 4 12 16 14 14)(4 4 12) simplegrading (1 1 1)
hex (0 2 3 1 10 12 13 11)(16 25 12) simpleGrading (1 1 1)
hex (2 4 5 3 12 14 15 13)(4 25 12) simpleGrading (1 1 1)
hex (4 6 7 5 14 16 17 15)(4 25 12) simpleGrading (1 1 1)
hex (6 8 9 7 16 18 19 17)(46 25 12) simpleGrading (1 1 1)

// Upper layer
hex (10 12 13 11 20 22 23 21)(16 25 12) simpleGrading (1 1 1)
hex (12 14 15 13 22 24 25 23)(4 25 12) simpleGrading (1 1 1)
hex (14 16 17 15 24 26 27 25)(4 25 12) simpleGrading (1 1 1)
hex (16 18 19 17 26 28 29 27)(46 25 12) simpleGrading (1 1 1)
);

edges
(
);

patches
(
patch XMIN
(
(0 1 11 10)
(10 11 21 20)
)
wall YMAX
(
(1 3 13 11)
(3 5 15 13)
(5 7 17 15)
(7 9 19 17)
(11 13 23 21)
(13 15 25 23)
(15 17 27 25)
(17 19 29 27)
)
patch XMAX
(
(8 9 19 18)
(18 19 29 28)
)
symmetryPlane YMIN
(
(0 2 12 10)
(2 6 16 12)
(6 8 18 16)
(10 12 22 20)
(16 18 28 26)
)
wall HULL
(
(12 16 14 14)
(12 14 24 22)
(14 16 26 24)
)
wall ZMIN
(
(2 6 4 4)
(0 2 3 1)
(2 4 5 3)
(4 6 7 5)
(6 8 9 7)
)
wall ZMAX
(
(20 22 23 21)
(22 24 25 23)
(24 26 27 25)
(26 28 29 27)
)
);

mergePatchPairs
(
);

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

ngj May 25, 2010 11:07

Apparently, the face

(4 14 14 4)

needs to be defined on the boundary as well. After applying that to any boundary patch, no defaultFace patch is generated.

Good luck,

Niels


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