[Gmsh] small gap mesh

[Christophe Geuzaine]

ZhouBin wrote:
> Dear Christophe,
> 
> Thank you very much for your patience. I have made one solution to my 
> last problem: put fine mesh around the circles.
> 
> However, as you could see from my latest version (.geo file), I have 
> some circles which are close to the boundary, the mesh is so skewed.
> 
> Since I  remember, Gmsh starts from line-->face-->volume, I really do to 
> know how to deal with these circles. (I do not want to decrease the 
> characteristic length for the whole domain, because of such close, small 
> gap).
> 
> Here I would like to send you my geo file, dear Christophe, if you have 
> time, would you mind to take a look?

The problem lies in the accuracy of the 1D mesh algorithm. You can
increase it with "Mesh.LcIntegrationPrecision=1.e-12;".

If this is too slow, you could also define attractors on the boundary.

> 
> Really appreciate your great advice.
> 
> Best regards,
> 
> Bin
> 
> 
> ------------------------------------------------------------------------
> From: zhoubinwx at hotmail.com
> To: cgeuzaine at ulg.ac.be
> CC: gmsh at geuz.org
> Subject: RE: [Gmsh] aspect ratio error
> Date: Sat, 15 Nov 2008 12:37:45 +0100
> 
> Dear Christophe,
> 
> I have a problem to control "aspect ratio".
> 
> Here I attach the geo file, after generating the mesh using Gmsh, I use 
> OpenFOAM to check the mesh, but I find that the aspect ratio is about 
> 14. My professor suggests me to use aspect ratio =2.
> 
> Could you please give me some hints about how to generate mesh with 
> given aspect ratio?
> 
> Best regards,
> 
> bin
> 
> ------------------------------------------------------------------------
> 使用新一代 Windows Live Messenger 轻松交流和共享！ 立刻下载！ 
> <http://im.live.cn/>
> ------------------------------------------------------------------------
> 使用新一代 Windows Live Messenger 轻松交流和共享！ 立刻下载！ 
> <http://im.live.cn/>


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine