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

To concave or not to concave, this is the answer!

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

Reply
 
LinkBack Thread Tools Display Modes
Old   September 22, 2010, 22:55
Default sHM works without snapEdge!
  #1
Senior Member
 
Ziad Boutanios
Join Date: Mar 2009
Location: Montréal, Canada
Posts: 113
Rep Power: 8
ziad is on a distinguished road
All you have to do is set maxConcave to a really small value. At least it seems to be the answer for getting a snappyHexMesh mesh without jagged/ragged edges on a rectangular geometry, without having to resort to snapeEdge.

Having spent some time looking at jagged/ragged edges I noticed that they boil down to faces with relatively higher concaveness. So armed with this hunch I started lowering the concaveness parameter maxConcave and noticed that the degree of jaggedness/raggedness decreased along with it. The magic number turned out to be 1 degree or maxConcave = 1.

The case is attached with all setup files for those who want to try it. Don't forget to run blockMesh first.

Now this is not guaranteed to work for everything and still needs to be tested for other geometries, such as pyramidal shapes for instance. It also does not mean that there is no such bug in sHM since OF is supposed to allow for concave faces and sHM should just work with them. The fix for this presumed bug could however turn out to be a very low local maxConcave for faces touching the line intersection of two surfaces.
Attached Images
File Type: jpg straightEdges.jpg (97.9 KB, 71 views)
Attached Files
File Type: gz testBuilding.tar.gz (7.7 KB, 10 views)

Last edited by ziad; September 23, 2010 at 11:29. Reason: added figure
ziad 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
About OpenFOAM and concave faces or cells mbeaudoin OpenFOAM Mesh Utilities 2 March 29, 2015 07:53
Problems on Tetrahedra to Polyhedra using polyDualMesh on concave surface object chnrdu OpenFOAM Pre-Processing 2 July 18, 2009 12:58
To red lemon pls answer K.Baker FLUENT 0 August 2, 2007 09:41
Appreciate for your any answer Klawu FLUENT 2 January 20, 2005 07:01
Has anyone heard of ANSWER code? J. Garroni Main CFD Forum 0 September 15, 1999 09:10


All times are GMT -4. The time now is 07:28.