[cfd1609496]

doing a structure of "T", i made 4 blocks and with mergepatchPairs done, there is still error exist. The following is my blockMeshdict:

 /*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 0.1;

vertices
(
    (1 0 0)
    (2 0 0)
    (2 1 0)
    (1 1 0)
    (1 0 0.1)
    (2 0 0.1)
    (2 1 0.1)
    (1 1 0.1)

    (0 1 0)
    (1 1 0)
    (1 2 0)
    (0 2 0)
    (0 1 0.1)
    (1 1 0.1)
    (1 2 0.1)
    (0 2 0.1)

    (1 1 0)
    (2 1 0)
    (2 2 0)
    (1 2 0)
    (1 1 0.1)
    (2 1 0.1)
    (2 2 0.1)
    (1 2 0.1)
    (2 1 0)
    (3 1 0)
    (3 2 0)
    (2 2 0)
    (2 1 0.1)
    (3 1 0.1)
    (3 2 0.1)
    (2 2 0.1)

);

blocks
(
    hex (0 1 2 3 4 5 6 7) (10 10 1) simpleGrading (1 1 1)
    hex (8 9 10 11 12 13 14 15) (10 10 1) simpleGrading (1 1 1)
    hex (16 17 18 19 20 21 22 23) (10 10 1) simpleGrading (1 1 1)
    hex (24 25 26 27 28 29 30 31) (10 10 1) simpleGrading (1 1 1)

);


edges
(
);

patches
(

patch i1

(
(3 7 6 2)
)

patch i2

(
(16 20 21 17)
)


patch i3

(
(9 13 14 10)
)


patch i4

(
(19 23 20 16)
)

patch i5

(
(18 22 21 17)
)


patch i6

(
(27 31 28 24)
)


);

mergePatchPairs
(
(i1 i2)
(i3 i4)
(i5 i6)
);

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

And the outcome after "Creating merge patch pairs

Adding point and face zones
Creating attachPolyTopoChanger"
was:
--> FOAM FATAL ERROR:
Face 730 reduced to less than 3 points.  Topological/cutting error B.
Old face: 2(484 605) new face: 2(252 373)

    From function void Foam::slidingInterface::coupleInterface(Foam::polyTopoChange&) const
    in file slidingInterface/coupleSlidingInterface.C at line 1768.

FOAM aborting

#0  Foam::error::printStack(Foam::Ostream&) at ??:?
#1  Foam::error::abort() at ??:?
#2  Foam::slidingInterface::coupleInterface(Foam::polyTopoChange&) const at ??:?
#3  Foam::slidingInterface::setRefinement(Foam::polyTopoChange&) const at ??:?
#4  Foam::polyTopoChanger::topoChangeRequest() const at ??:?
#5  Foam::polyTopoChanger::changeMesh(bool, bool, bool, bool) at ??:?
#6  Foam::attachPolyTopoChanger::attach(bool) at ??:?
#7  ? in "/opt/openfoam6/platforms/linux64GccDPInt32Opt/bin/blockMesh"
#8  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#9  ? in "/opt/openfoam6/platforms/linux64GccDPInt32Opt/bin/blockMesh"
Aborted (core dumped)

Is there a need to use stitchMesh or any other things i should look out?
Thanks and appreciate your time.

Sincerely,
yh