CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > OpenFOAM > OpenFOAM Meshing & Mesh Conversion

[blockMesh] mesh causing problems with convergence

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

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 22, 2012, 17:00
Default mesh causing problems with convergence
  #1
New Member
 
Join Date: Jun 2012
Posts: 5
Rep Power: 13
Tetragramm is on a distinguished road
I'm having problems with my mesh causing divergence. I'm trying to replicate the results in this PDF here but the mesh I've created has issues are causing simpleFoam to diverge. For some reason, the solution is only diverging at higher angles of attack.

I've put together a set of pictures showing the problem and my geometry. They are located here. For some reason, all along the join between the four hex blocks, the solution diverges. The most extreme example is the portion pictured in the album.

I'm not sure if the non-ortho faces that checkMesh finds are the source of the problem. There are some right at the wingtip, where the most extreme divergence is, but the divergence continues all the way out, but there are no non-ortho faces that far out.

I'm hoping that one of you can tell me how to fix the problem without having to re-do the whole blockMesh file. Or, if you say that's not possible, to give me recommendations on how to make this geometry without causing bad cells and faces in the mesh. I'd like any suggestions to keep in mind that I will be changing things like airfoils and aspect ratio, so it should be automation friendly.

Thank you for you help.

I've attached my blockMesh file and this is my checkMesh file
Code:
/*---------------------------------------------------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  2.1.1                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.org                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
Build  : 2.1.1-221db2718bbb
Exec   : checkMesh
Date   : Sep 22 2012
Time   : 13:54:28
Host   : "Heterodyne"
PID    : 2781
Case   : /home/tetragramm/OpenFOAM/0012
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Disallowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create polyMesh for time = 0

Time = 0

Mesh stats
    points:           4040101
    faces:            12040000
    internal faces:   11920000
    cells:            4000000
    boundary patches: 4
    point zones:      0
    face zones:       0
    cell zones:       0

Overall number of cells of each type:
    hexahedra:     3960000
    prisms:        40000
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces ...
    Patch               Faces    Points   Surface topology                  
    movingWall          40000    40001    ok (non-closed singly connected)  
    fixedWalls          40000    40001    ok (non-closed singly connected)  
    symmetricWall       40000    40400    ok (non-closed singly connected)  
    allAround           0        0        ok (empty)                        

Checking geometry...
    Overall domain bounding box (-2.59808 -2.84808 0) (2.59808 2.34808 3)
    Mesh (non-empty, non-wedge) directions (1 1 1)
    Mesh (non-empty) directions (1 1 1)
    Boundary openness (-2.07313e-15 -5.50671e-15 5.79448e-15) OK.
    Max cell openness = 1.74778e-15 OK.
    Max aspect ratio = 149.528 OK.
    Minumum face area = 4.19645e-07. Maximum face area = 0.00338268.  Face area magnitudes OK.
    Min volume = 1.46671e-09. Max volume = 7.5958e-05.  Total volume = 30.7017.  Cell volumes OK.
    Mesh non-orthogonality Max: 86.9482 average: 28.9597
   *Number of severely non-orthogonal faces: 24795.
    Non-orthogonality check OK.
  <<Writing 24795 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
 ***Max skewness = 11.086, 9003 highly skew faces detected which may impair the quality of the results
  <<Writing 9003 skew faces to set skewFaces
    Coupled point location match (average 0) OK.

Failed 1 mesh checks.

End
Attached Files
File Type: txt blockMeshDict.txt (31.5 KB, 5 views)
Tetragramm is offline   Reply With Quote

Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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 Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Moving mesh Niklas Wikstrom (Wikstrom) OpenFOAM Running, Solving & CFD 122 June 15, 2014 07:20
[ICEM] issue occur after extrude 2D airfoil mesh and convergence problem in CFX shiyun ANSYS Meshing & Geometry 4 May 9, 2012 20:55
[Gmsh] 2D Mesh Generation Tutorial for GMSH aeroslacker OpenFOAM Meshing & Mesh Conversion 12 January 19, 2012 04:52
[snappyHexMesh] snappyHexMesh won't work - zeros everywhere! sc298 OpenFOAM Meshing & Mesh Conversion 2 March 27, 2011 22:11
Convergence moving mesh lr103476 OpenFOAM Running, Solving & CFD 30 November 19, 2007 15:09


All times are GMT -4. The time now is 13:01.