[ivanyao]

hi,
i am use OF1.4,i don't know how to increase Mesh near the surface of the model?

[ngj]

If you talk about the surface of some multiphase flow, then I do not think it is straight forward.

If you talk about increasing the number of computational cells toward the boundaries of your computational domain, then look into the user guide, the meshing chapter and especially the grading routines.

- Niels

[ivanyao]

hi,
I think i have got your message.thank you!

[ivanyao]

hi,
i have followed your suggestion.but it can not increase nunber of the cells.my blockMesh.file are follow:
vertices
(
(-3 -3 0)
(3 -3 0)
(3 3 0)
(-3 3 0)
(-3 -3 6)
(3 -3 6)
(3 3 6)
(-3 3 6)
(-39 -3 0)
(-39 3 0)
(-39 -3 6)
(-39 3 6)
(153 -3 0)
(153 3 0)
(153 -3 6)
(153 3 6)
(-3 -60 0)
(3 -60 0)
(-3 -60 6)
(3 -60 6)
(-3 60 0)
(3 60 0)
(-3 60 6)
(3 60 6)
(-39 -60 0)
(153 -60 0)
(153 60 0)
(-39 60 0)
(-39 -60 6)
(153 -60 6)
(153 60 6)
(-39 60 6)
(-39 -60 60)
(153 -60 60)
(153 60 60)
(-39 60 60)
(-39 -3 60)
(-39 3 60)
(-3 -60 60)
(3 -60 60)
(153 -3 60)
(153 3 60)
(-3 60 60)
(3 60 60)
(-3 -3 60)
(3 -3 60)
(3 3 60)
(-3 3 60)
);

blocks
(
hex (24 16 0 8 28 18 4 10) (36 57 6) simpleGrading (1 1 1)
hex (28 18 4 10 32 38 44 36) (36 57 54) simpleGrading (1 1 1)
hex (16 17 1 0 18 19 5 4) (6 57 6) simpleGrading (1 1 1)
hex (18 19 5 4 38 39 45 44) (6 57 54) simpleGrading (1 1 1)
hex (17 25 12 1 19 29 14 5) (150 57 6) simpleGrading (1 1 1)
hex (19 29 14 5 39 33 40 45) (150 57 54) simpleGrading (1 1 1)
hex (1 12 13 2 5 14 15 6) (150 6 6) simpleGrading (1 1 1)
hex (5 14 15 6 45 40 41 46) (150 6 54) simpleGrading (1 1 1)
hex (2 13 26 21 6 15 30 23) (150 57 6) simpleGrading (1 1 1)
hex (6 15 30 23 46 41 34 43) (150 57 54) simpleGrading (1 1 1)
hex (3 2 21 20 7 6 23 22) (6 57 6) simpleGrading (1 1 1)
hex (7 6 23 22 47 46 43 42) (6 57 54) simpleGrading (1 1 1)
hex (9 3 20 27 11 7 22 31) (36 57 6) simpleGrading (1 1 1)
hex (11 7 22 31 37 47 42 35) (36 57 54) simpleGrading (1 1 1)
hex (8 0 3 9 10 4 7 11) (36 6 6) simpleGrading (1 1 1)
hex (10 4 7 11 36 44 47 37) (36 6 54) simpleGrading (1 1 1)
hex (4 5 6 7 44 45 46 47) (6 6 54) simpleGrading (1 1 1)
);

edges
(
);

patches
(
patch inlet
(
(27 9 11 31)
(37 11 31 35)
(9 8 10 11)
(11 10 36 37)
(8 24 28 10)
(10 28 32 36)
)
patch outlet
(
(25 12 14 29)
(29 14 40 33)
(12 13 15 14)
(14 15 41 40)
(13 26 30 15)
(15 30 34 41)
)
wall front
(
(0 3 7 4)
)
wall <back>
(
(1 2 6 5)
)
wall <left>
(
(0 1 5 4)
)
wall <right>
(
(2 3 7 6)
)
wall <top>
(
(4 5 6 7)
)
empty <wall>
(
(24 16 18 28)
(28 18 38 32)
(16 17 19 18)
(18 19 39 38)
(17 25 29 19)
(19 29 33 39)
(26 21 23 30)
(30 23 43 34)
(21 20 22 23)
(23 22 42 43)
(20 27 31 22)
(22 31 35 42)
(32 38 44 36)
(44 36 37 47)
(47 37 35 42)
(38 39 45 44)
(44 45 46 47)
(47 46 43 42)
(39 33 40 45)
(40 45 46 41)
(41 46 43 34)
(16 24 8 0)
(0 8 9 3)
(3 9 27 20)
(17 16 0 1)
(2 3 20 21)
(25 17 1 12)
(12 1 2 13)
(13 2 21 26)
)
wall <bottom>
(
)
);

mergePatchPairs
(
);
I change the simpleGrading(1 1 1) by (1 1 5).my geometry is very simple ,just put the 6*6*6 cube into 192*120*60 box.my purpose is increasing grid near the surface of the cube.
would someone help me?

[ivanwhlau]

Hi, WeiHong,

First of all, changing simpleGrading, which is cell expansion ratios, will not increase the number of cells.
Read the manual here:
http://www.opencfd.co.uk/openfoam/do...#x25-1390005.3

Hmm.. I see what you try to do. Well, where do you put that (1 1 5)? If you really want to intensively increase the number of cells close to surface, I recommend you to add one more strip above.. It is not too hard, but tedious, somehow.

iL

[ivanyao]

hi,ivan,
thank you for giving the feedback! first, i put the (1 1 5)into simpleGrading of the blocks,as follow:
hex (24 16 0 8 28 18 4 10) (36 57 6) simpleGrading (1 1 5)
hex (28 18 4 10 32 38 44 36) (36 57 54) simpleGrading (1 1 5)
hex (16 17 1 0 18 19 5 4) (6 57 6) simpleGrading (1 1 5)
hex (18 19 5 4 38 39 45 44) (6 57 54) simpleGrading (1 1 5)
hex (17 25 12 1 19 29 14 5) (150 57 6) simpleGrading (1 1 5)
hex (19 29 14 5 39 33 40 45) (150 57 54) simpleGrading (1 1 5)
hex (1 12 13 2 5 14 15 6) (150 6 6) simpleGrading (1 1 5)
hex (5 14 15 6 45 40 41 46) (150 6 54) simpleGrading (1 1 5)
hex (2 13 26 21 6 15 30 23) (150 57 6) simpleGrading (1 1 5)
hex (6 15 30 23 46 41 34 43) (150 57 54) simpleGrading (1 1 5)
hex (3 2 21 20 7 6 23 22) (6 57 6) simpleGrading (1 1 5)
hex (7 6 23 22 47 46 43 42) (6 57 54) simpleGrading (1 1 5)
hex (9 3 20 27 11 7 22 31) (36 57 6) simpleGrading (1 1 5)
hex (11 7 22 31 37 47 42 35) (36 57 54) simpleGrading (1 1 5)
hex (8 0 3 9 10 4 7 11) (36 6 6) simpleGrading (1 1 5)
hex (10 4 7 11 36 44 47 37) (36 6 54) simpleGrading (1 1 5)
hex (4 5 6 7 44 45 46 47) (6 6 54) simpleGrading (1 1 5)
);
is that the only way to increase the grid close the surface of cube?you mean that create more vertices and blocks?

[ivanwhlau]

hi, weihong,
Yes, you can create more vertices and blocks next to surface and increase the number of cells here. Does your blockMesh work? If so, what you did now is to put the bottom cells with closer space and the top cells far apart....
Did you follow the meshing routine like what Niels suggest? Read words by words on manual of Meshing. You can easily solve this problem.
Regards,
iL

[ivanyao]

hi，
thank you！i solved the problem. thank you!