blockMesh

First step is to create a dummy folder with the tutorial command:

restore0Dir

blockMesh is a cartesian mesh generators which relies on a single dictionary located at system/blockMeshDict. The programme starts executing in terminal:

blockMesh

The mesh will be generated inside the folder constant/polyMesh. Parameters to control this command is in system/blockMeshDict which defines the domain through vertices, define the blocks and set the number of elements in the segment.

Warning: Be consistent – side of different blocks must contain the same number on elements and bias. In blockMesh.boundary, use the rule of the right hand to create the normal to the surface towards the intern of the body.

An example is posted here from the tutorial /opt/OpenFOAM/OpenFOAM-v2206/tutorials/multiphase/interFoam/RAS/damBreak:

FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

scale   0.146;

vertices
(
    (0 0 0)
    (2 0 0)
    (2.16438 0 0)
    (4 0 0)
    (0 0.32876 0)
    (2 0.32876 0)
    (2.16438 0.32876 0)
    (4 0.32876 0)
    (0 4 0)
    (2 4 0)
    (2.16438 4 0)
    (4 4 0)
    (0 0 0.1)
    (2 0 0.1)
    (2.16438 0 0.1)
    (4 0 0.1)
    (0 0.32876 0.1)
    (2 0.32876 0.1)
    (2.16438 0.32876 0.1)
    (4 0.32876 0.1)
    (0 4 0.1)
    (2 4 0.1)
    (2.16438 4 0.1)
    (4 4 0.1)
);

blocks
(
    hex (0 1 5 4 12 13 17 16) (23 8 1) simpleGrading (1 1 1)
    hex (2 3 7 6 14 15 19 18) (19 8 1) simpleGrading (1 1 1)
    hex (4 5 9 8 16 17 21 20) (23 42 1) simpleGrading (1 1 1)
    hex (5 6 10 9 17 18 22 21) (4 42 1) simpleGrading (1 1 1)
    hex (6 7 11 10 18 19 23 22) (19 42 1) simpleGrading (1 1 1)
);

edges
(
);

boundary
(
    leftWall
    {
        type wall;
        faces
        (
            (0 12 16 4)
            (4 16 20 8)
        );
    }
    rightWall
    {
        type wall;
        faces
        (
            (7 19 15 3)
            (11 23 19 7)
        );
    }
    lowerWall
    {
        type wall;
        faces
        (
            (0 1 13 12)
            (1 5 17 13)
            (5 6 18 17)
            (2 14 18 6)
            (2 3 15 14)
        );
    }
    atmosphere
    {
        type patch;
        faces
        (
            (8 20 21 9)
            (9 21 22 10)
            (10 22 23 11)
        );
    }
);

mergePatchPairs
(
);