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

[snappyHexMesh] To concave or not to concave, this is the answer!

Register Blogs Community New Posts Updated Threads Search

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   September 22, 2010, 22:55
Default To concave or not to concave, this is the answer!
  #1
Senior Member
 
Join Date: Mar 2009
Location: My oyster
Posts: 124
Rep Power: 17
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, 116 views)
Attached Files
File Type: gz testBuilding.tar.gz (7.7 KB, 14 views)

Last edited by ziad; September 23, 2010 at 11:29. Reason: added figure
ziad is offline   Reply With Quote

Reply


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
[Technical] About OpenFOAM and concave faces or cells mbeaudoin OpenFOAM Meshing & Mesh Conversion 4 October 13, 2021 06:54
[mesh manipulation] Sharp edge problem on concave patches using polyDualMesh without error keepfit OpenFOAM Meshing & Mesh Conversion 1 November 25, 2014 14:28
[snappyHexMesh] snappyHexMesh and concave cells GerhardHolzinger OpenFOAM Meshing & Mesh Conversion 2 December 16, 2013 09:43
does anyone answer or give some comment about my questions??? Z. Chang Main CFD Forum 7 May 9, 2000 10:15
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 18:54.