CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Bugs

Extrudemesh

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

Reply
 
LinkBack Thread Tools Display Modes
Old   June 12, 2009, 09:29
Default Extrudemesh
  #1
Member
 
Niklas Wikstrom
Join Date: Mar 2009
Posts: 85
Rep Power: 8
wikstrom is on a distinguished road
Hi,

I think there is a serious bug in extrudeMesh. Using the linearNormal model, all cells created become inside out. Extruding with negative thickness produces a valid mesh. (that ofcourse can be moved into the desired place with transformPoints, but this workaraound feels a bit awkward.)

Attacheed is a test case describing this. Run the included run.sh with argument negative and positive.

Cheers
Niklas
Attached Files
File Type: gz extrudeTest.tar.gz (2.4 KB, 19 views)
wikstrom is offline   Reply With Quote

Old   June 16, 2009, 07:21
Default
  #2
Super Moderator
 
Mattijs Janssens
Join Date: Mar 2009
Posts: 1,416
Rep Power: 16
mattijs is on a distinguished road
Hi Niklas,

the normal is indeed reversed. Agree it is probably not logical. I'd rather not change the behaviour in 1.5.x but will in future versions.

Thanks,

Mattijs
mattijs is offline   Reply With Quote

Old   December 6, 2009, 07:59
Default extrudeMesh - hexa cells generated?
  #3
New Member
 
Bence Somogyi
Join Date: Mar 2009
Location: Graz, Austria
Posts: 6
Rep Power: 8
sbence is on a distinguished road
Dear Foamers,

I am trying to create a 2D mesh to be used in OpenFOAM with snappy. My method is the following:
  1. create a mesh in snappy, thickness should be large enough to have a few nice layers in the middle
  2. create a cellSet containing these nice layers in the middle
  3. create new mesh based on the cellSet with subsetMesh; the new mesh has almost planar patches on the sides
  4. autoPatch and select a face for extrusion
  5. extrudMesh using the right patch
My problem is that the generated mesh contains hexa cells and pyramids as well. So it is not a real extrusion, because the extrusion would result in hexas and wedges only.

Some explanatory screenshots:
Result with snappy:

cellSet from the middle:

new mesh from cellSet:

patch to extrude (why the triangles are not visualized in paraview?):

result mesh with extrudeMesh:

the same visualized in engrid. different colors > different cell types:

pyramids visualized in engrid:

tetras visualized in engrid:


How can I avoid pyramids/tetras?

Thanks for any help!

Bence
sbence is offline   Reply With Quote

Reply

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
Import netgen mesh to OpenFOAM hsieh Open Source Meshers: Gmsh, Netgen, CGNS, ... 32 September 13, 2011 05:50
ExtrudeMesh segersson OpenFOAM Mesh Utilities 5 August 22, 2011 11:23
Converting mesh from gmsh newbee OpenFOAM Pre-Processing 21 January 22, 2010 07:51
ExtrudeMesh for Dummies wolle1982 OpenFOAM Mesh Utilities 2 October 28, 2008 11:35
Utility to extrude into 3D mesh from a 2D mesh hsieh OpenFOAM Meshing & Mesh Conversion 1 April 9, 2006 05:37


All times are GMT -4. The time now is 15:44.