[sarajags_89]

Hi I wanted to try the merge patchpair option ...I couldnt figure out where I went wrong..
help pls
/*--------------------------------*- 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
(
(0 0 0)
(3 0 0)
(0 0 1)
(3 0 1)
(0 1 0)
(3 1 0)
(0 1 1)
(3 1 1)
(0 0 2)
(3 0 2)
(0 0 3)
(3 0 3)
(0 1 2)
(3 1 2)
(0 1 3)
(3 1 3)
);

blocks
(
hex (0 1 2 3 4 5 6 7) (20 20 1) simpleGrading (1 1 1)
hex (8 9 10 11 12 13 14 15 ) (20 20 1) simpleGrading (1 1 1)
);

edges
(
);

patches
(
wall fixedWalls
(//walls of block 1
(7 5 4 6)
(0 4 5 1)
(5 7 3 1)
(0 1 3 2)
(6 2 3 7)
(4 0 2 6)
//walls of block2
(8 12 13 9)
(9 13 15 11)
(11 10 14 15)
(9 11 10 8)
(10 8 12 14)
)
empty frontAndBack
(

)
);

mergePatchPairs
(
(<8 12 13 9> <6 2 3 7>) //merge patch pair 0
);

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

[tstovall]

The inputs for mergePatchPairs are patch names. Make your blockMeshDict file look like this:

...
patches
(
wall fixedWalls
(//walls of block 1
(7 5 4 6)
(0 4 5 1)
(5 7 3 1)
(0 1 3 2)
// (6 2 3 7) remove this face for stitching
(4 0 2 6)
//walls of block2
// (8 12 13 9) remove this face for stitching
(9 13 15 11)
(11 10 14 15)
(9 11 10 8)
(10 8 12 14)
)
patch stitchPatch1
(
(6 2 3 7) \\rename face here for stitching
)
patch stitchPatch2
(
(8 12 13 9) \rename face here for stitching
)

);

mergePatchPairs
(
( stitchPatch1 stitchPatch2 ) \\ use patch names as input for mergePatchPairs
);

This should work for you.

On another issue: I've been getting error messages with the mergePatchPairs feature as follows: Any ideas on how to fix this? I've checked the mesh and the faces for merging are of the same size and flush together.

blockMesh output...

Creating cells

Creating patches

Creating mesh from block mesh

Default patch type set to empty
Creating merge patch pairs

Adding point and face zones
Creating attachPolyTopoChanger


Duplicate point found in cut face. Error in the face cutting algorithm for global face 4(166534 166615 166616 166535) local face 4(478 479 483 482)
Slave size: 1920 Master size: 1920 index: 397.
Face: 4(162889 162970 166616 162890)