[Samsam2]

Hello,
How I can define number of cells in my blockmeshDict:
blocks
(
hex (0 9 8 1 10 19 18 11) (16 16 216) simpleGrading (1 1 1)
hex (1 8 5 2 11 18 15 12) (16 16 216) simpleGrading (1 1 1)
hex (2 5 4 3 12 15 14 13) (16 16 216) simpleGrading (1 1 1)
hex (8 7 6 5 18 17 16 15) (16 16 216) simpleGrading (1 1 1)
);

I dont know how (16 16 216) is defined?? AS I want to use this code for other geometry and dont know where I should find number of cells in x, y and Z direction.
Thank you,

[Carlo_P]

Hey,
you can have a look into:
http://www.wolfdynamics.com/wiki/mes..._blockmesh.pdf

In this case:
blocks
(
hex (0 9 8 1 10 19 18 11) (16 16 216) simpleGrading (1 1 1)
hex (1 8 5 2 11 18 15 12) (16 16 216) simpleGrading (1 1 1)
hex (2 5 4 3 12 15 14 13) (16 16 216) simpleGrading (1 1 1)
hex (8 7 6 5 18 17 16 15) (16 16 216) simpleGrading (1 1 1)
);

16 16 216 are the number of cells respectively in x,y,z direction.
The (1 1 1) is the value of grading, if you want to have an homogeneous division.
If you are an user, use always (1 1 1).
Another trick: try to use the same dimension (number of cells/extension of the box) in every direction, in order to start with an homogenus mesh.

[Samsam2]

Hello Carlo,
Thank you so much for your answer. If I change the number of cells to (16 16 16), does it make any problem for my results accuracy?
because my geometry dimension is not the same in XY and Z direction.
Thnak you,

[Carlo_P]

Yes, if you change in (16 16 16) you should have a coarser mesh, so, probably a less accurate result.
Furthermore, you can also have stability problem, due to the small quality of the mesh, since the blockMesh cells are very not regular.
You have to set the (xcell ycell zcell) in order to have a quite regular hexaedral, so the xcell should be xlength/cellDimension
ycell should be ylength/cellDimension
zcell should be zlength/cellDimension

where cellDimension should the same.

Obviously, this is a very simple first rule.

[Samsam2]

Hello Carlo,
Thank you so much for your reply. I dont know what is wrong with my mesh. I get error of "Inconsistent number of faces between block pair 0 and 1". Here is copy of my blockmesh dict:
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}

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

scale 1;

vertices
(
(-296 -296.6 -5000)
(-296 -296.6 2192)
(-296 -296.6 2792)
(-296 -296.6 2992)
(-296 296.6 2992)
(-296 296.6 2792)
(-296 396.6 2792)
(-296 396.6 2192)
(-296 296.6 2192)
(-296 296.6 -5000)
(296 -296.6 -5000)
(296 -296.6 2192)
(296 -296.6 2792)
(296 -296.6 2992)
(296 296.6 2992)
(296 296.6 2792)
(296 396.6 2792)
(296 396.6 2192)
(296 296.6 2192)
(296 296.6 -5000)

);
blocks
(
hex (0 9 8 1 10 19 18 11) (16 16 194) simpleGrading (1 1 1)
hex (1 8 5 2 11 18 15 12) (16 16 22) simpleGrading (1 1 1)
hex (2 5 4 3 12 15 14 13) (16 16 5) simpleGrading (1 1 1)
hex (8 7 6 5 18 17 16 15) (16 2 22) simpleGrading (1 1 1)
);

edges
(
);

boundary
(
frontAndBack
{
type wall;
faces
(
(10 11 18 19)
(11 12 15 18)
(12 13 14 15)
(18 15 16 17)
(9 8 1 0)
(8 5 2 1)
(5 4 3 2)
(7 6 5 8)
);
}
walls
{
type wall;
faces
(
(0 1 11 10)
(1 2 12 11)
(2 3 13 12)
(15 14 4 5)
(16 15 5 6)
(18 17 7 8)
(19 18 8 9)
);
}
outlet
{
type patch;
faces
(
(0 10 19 9)
);
}
inletone
{
type patch;
faces
(
(3 13 14 4)
);
}
inlettwo
{
type patch;
faces
(
(17 16 6 7)
);
}
);

Could you please help me how to solve this problem?
Thanks alot!