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-   -   Wedge type mesh: generation OK but the mesh has bug for some cells! (http://www.cfd-online.com/Forums/openfoam-meshing-blockmesh/128458-wedge-type-mesh-generation-ok-but-mesh-has-bug-some-cells.html)

Paebin January 13, 2014 05:50

Wedge type mesh: generation OK but the mesh has bug for some cells!
 
2 Attachment(s)
Hello,

I'm working on a case (flow inside a nozzle) where my geometry is axisymmetric and I want to do simulation with only one quarter of it (for cpu time saving).

I create my mesk by generating a .m4 file with Matlab and then create a blockMeshDict file with this .m4 file (I know that can sound complicated, but it works).

The mesh is generating without any problem. But I have a block that gets some bad cells (you can see it on the attached image from paraview) and I don't know why! This block has only 6 vertices because it is on the axis.

I have isolated this particular block in order to understand the bug easier, here is my blockMeshDict:

PHP Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.2.2                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    
version     2.0;
    
format      ascii;
    class       
dictionary;
    
object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

 
convertToMeters 1.000000e-06;
 
 
vertices 
 
(
 
//front
 
(             400               0               0 // 0 pt 4 (p4f) 
 
(             450               0               0 // 1 pt 15 (p15f) 
 
(             450 24.7487373415292 -24.7487373415292 // 2 pt 54 (p18b) 
 
(             400 24.7487373415292 -24.7487373415292 // 3 pt 41 (p5b) 
  
 //back
 
(             450 24.7487373415292 24.7487373415292 // 4 pt 18 (p18f) 
 
(             400 24.7487373415292 24.7487373415292 // 5 pt 5 (p5f)
 
);
 
 
blocks 
 
(
 
hex (0 1 2 3 0 1 4 5// i 
 
20 7 16
 
simpleGrading (5 1 1// sens XYZ
 
);
 
 
edges 
 
(
 );
 
 
boundary 
 
(
  );
 
 
mergePatchPairs 
 
(
 ); 

I have attached a simple case with the mesh, it doesn't work of course because I don't have any patch, but you can generate and visualize the mesh.

What am I doing wrong ?? I have other blocks that have the same configuration (6 vertices, on the axis) but they are all good, I don't understand!

Paebin January 13, 2014 06:23

I didn't mention it, but I use openFoam 2.2.2. ;)


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