CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Native Meshers: blockMesh

Creating O-meshes

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   October 26, 2009, 09:44
Default Creating O-meshes
  #1
Senior Member
 
MadsR's Avatar
 
Mads Reck
Join Date: Aug 2009
Location: Copenhagen, Denmark
Posts: 175
Rep Power: 10
MadsR is on a distinguished road
Hi.

I need to make an O-mesh using blockMesh, is someone able to help me out?
I need it for an airfoil, but a cylinder-example or the like would be great.


Thanks a lot!

/Mads
__________________
Online free airfoil-mesher for OpenFOAM here
MadsR is offline   Reply With Quote

Old   October 26, 2009, 12:56
Default
  #2
Senior Member
 
akidess's Avatar
 
Anton Kidess
Join Date: May 2009
Location: Delft, Netherlands
Posts: 1,133
Rep Power: 20
akidess will become famous soon enough
There you go. This mesh has refinement towards both ends of the cylinder, so it could be simplified to use only five blocks.

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

convertToMeters 0.025;

vertices
(
    (0.21 0.21 0)
    (-0.21 0.21 0)
    (-0.21 -0.21 0)
    (0.21 -0.21 0)
    (0.21 0.21 1.2)
    (-0.21 0.21 1.2)
    (-0.21 -0.21 1.2)
    (0.21 -0.21 1.2)
    (0.353553 0.353553 0)
    (-0.353553 0.353553 0)
    (-0.353553 -0.353553 0)
    (0.353553 -0.353553 0)
    (0.353553 0.353553 1.2)
    (-0.353553 0.353553 1.2)
    (-0.353553 -0.353553 1.2)
    (0.353553 -0.353553 1.2)
    (0.21 0.21 0.6)
    (-0.21 0.21 0.6)
    (-0.21 -0.21 0.6)
    (0.21 -0.21 0.6)
    (0.353553 0.353553 0.6)
    (-0.353553 0.353553 0.6)
    (-0.353553 -0.353553 0.6)
    (0.353553 -0.353553 0.6)
);

blocks
(
    // center block 1
    hex (2 3 0 1 18 19 16 17) (23 23 53) simpleGrading (1 1 2.5)
    // right 1
    hex (3 11 8 0 19 23 20 16) (17 23 53) simpleGrading (1 1 2.5)
    // top 1
    hex (1 0 8 9 17 16 20 21) (23 17 53) simpleGrading (1 1 2.5)
    // left 1
    hex (10 2 1 9 22 18 17 21) (17 23 53) simpleGrading (1 1 2.5)
    // bottom 1
    hex (10 11 3 2 22 23 19 18) (23 17 53) simpleGrading (1 1 2.5)

    // center block 2
    hex (18 19 16 17 6 7 4 5) (23 23 53) simpleGrading (1 1 0.4)
    // right 2
    hex (19 23 20 16 7 15 12 4) (17 23 53) simpleGrading (1 1 0.4)
    // top 2
    hex (17 16 20 21 5 4 12 13) (23 17 53) simpleGrading (1 1 0.4)
    // left 2
    hex (22 18 17 21 14 6 5 13) (17 23 53) simpleGrading (1 1 0.4)
    // bottom 2
    hex (22 23 19 18 14 15 7 6) (23 17 53) simpleGrading (1 1 0.4)
);

edges
(
    arc 11 8 (0.5 0 0)
    arc 8 9 (0 0.5 0)
    arc 9 10 (-0.5 0 0)
    arc 10 11 (0 -0.5 0)
    arc 15 12 (0.5 0 1.2)
    arc 12 13 (0 0.5 1.2)
    arc 13 14 (-0.5 0 1.2)
    arc 14 15 (0 -0.5 1.2)
    arc 23 20 (0.5 0 0.6)
    arc 20 21 (0 0.5 0.6)
    arc 21 22 (-0.5 0 0.6)
    arc 22 23 (0 -0.5 0.6)
);

patches
(
    wall sideWalls
    (
        (11 23 20 8)
        (23 15 12 20)
        (8 20 21 9)
        (20 12 13 21)
        (9 10 22 21)
        (21 22 14 13)
        (10 11 23 22)
        (22 23 15 14)
    )

    wall bottomWall
    (
        (2 3 0 1)
        (3 11 8 0)
        (0 8 9 1)
        (2 1 9 10)
        (2 10 11 3)
    )

    wall topWall
    (
        (6 7 4 5)
        (7 15 12 4)
        (4 12 13 5)
        (6 5 13 14)
        (6 14 15 7)
    )

);

mergePatchPairs
(
);

// ************************************************************************* //
akidess is offline   Reply With Quote

Old   October 29, 2009, 05:40
Default
  #3
Senior Member
 
MadsR's Avatar
 
Mads Reck
Join Date: Aug 2009
Location: Copenhagen, Denmark
Posts: 175
Rep Power: 10
MadsR is on a distinguished road
Thanks Anton.

I am trying to extend this to a mesh around an airfoil, and it's pretty hard (well, in principle it's simple, but it's so tedious work :-) ). You wouldn't happen to have a version for an airfoil which might be easier to extend? I'd like to make an automatic blockMeshDict generator for airfoil meshes (say, from a x,y,z airfoil-data file).

/Mads
__________________
Online free airfoil-mesher for OpenFOAM here
MadsR is offline   Reply With Quote

Old   October 29, 2009, 13:00
Default
  #4
Senior Member
 
akidess's Avatar
 
Anton Kidess
Join Date: May 2009
Location: Delft, Netherlands
Posts: 1,133
Rep Power: 20
akidess will become famous soon enough
Unfortunately that's all I have, I've never tried to mesh an airfoil. Slightly offtopic, but isn't the mesh you need C-type? Because it collapses at the thin side of the foil?

Wouldn't it be possible to have your airfoil data-file as STL, and then just make the mesh with snappyHexMesh?
akidess is offline   Reply With Quote

Old   October 30, 2009, 03:39
Default
  #5
Senior Member
 
MadsR's Avatar
 
Mads Reck
Join Date: Aug 2009
Location: Copenhagen, Denmark
Posts: 175
Rep Power: 10
MadsR is on a distinguished road
Anton, you are absolutely right about the C-mesh, typically used. But my airfoil has a blunt trailing edge (it's truncated and sharp), and an o-mesh is probably best in such cases.

I have tried snappyHexMesh (I think this tool is great, and I am looking forward to it being improved even more) but it has trouble with capturing the sharp trailing edge AND having it making boundary layers never really worked out for me...
__________________
Online free airfoil-mesher for OpenFOAM here
MadsR is offline   Reply With Quote

Reply

Tags
blockmesh, o-mesh

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Automatic Mesh Refinement and Tetrahedral Meshes philippose OpenFOAM Meshing Format & General Technical 8 May 21, 2016 15:44
Getting prism to inflate into mixed tet-hex meshes Joe CFX 16 October 10, 2011 07:06
Tutorial for Creating Simple 3D Meshes jonlemur OpenFOAM Native Meshers: blockMesh 4 August 8, 2007 13:20
Problems with Meshing: Collapsed Cells Emmanuel Resch CD-adapco 1 July 30, 2007 03:02
Large 3D tetrahedral meshes Aldo Bonfiglioli Main CFD Forum 4 August 27, 1999 03:33


All times are GMT -4. The time now is 10:07.