meshing issue
 

hii every one
i am new to openFoam and trying to creat circular patch for particle injection of patch injection model and getting this error while creating circle please help me with this
face 0 in patch 2 does not have neighbour cell face: 4(8 10 9 8)

convertToMeters 0.001;

vertices
(
(-7.5 -75 0) //0
( 7.5 -75 0) //1
( 7.5 75 0) //2
(-7.5 75 0) //3
(-7.5 -75 450) //4
( 7.5 -75 450) //5
( 7.5 75 450) //6
(-7.5 75 450) //7
(0 0 0) //8
(0 2 0) //9
(0 -2 0) //10
);

blocks
(
hex (0 1 2 3 4 5 6 7) (1 15 45) simpleGrading (1 1 1)
);

edges
(
arc 9 10 (-2 0 0)
arc 10 9 (2 0 0)
);

boundary
(
top
{
type patch;
faces
(
(4 5 6 7)
);
}

bottom
{
type patch;
faces
(
(0 3 2 1)
);
}

circle
{
type patch;
faces
(
(8 10 9 8)
(8 9 10 8)
);
}

walls
{
type wall;
faces
(
(0 1 5 4)
(2 3 7 6)
);
}

frontAndBack
{
type symmetry;
faces
(
(1 2 6 5)
(3 0 4 7)
);
}
);

mergePatchPairs
(
(bottom circle)
);

https://drive.google.com/file/d/1QvD...ew?usp=sharing
// ************************************************** ***********************

Any face should either have a neighbour or a boundary condition. The face in question has non of these.

thank you sir
can you suggest me any lecture or tutorial on this like creating geometry patches and merging it

There are many sources for what you are looking for. First read OpenFOAM documentation - there is a fairly good explanation of how to use blockMesh. Additionally, from the top of my head, you could try the tutorials in the wiki page: https://wiki.openfoam.com/Meshing

Best,
Petros