[Gmsh] 2D refinement around a line

GERALD sophie DSNA/CC sophie.gerald at onera.fr
Fri Mar 11 13:00:09 CET 2011


Geordie McBain wrote:
> 2011/3/11 GERALD sophie DSNA/CC <sophie.gerald at onera.fr>:
>   
>> Good evening,
>>
>> I work with the "gmsh-2.5.0-Linux" version of your software. By the way,
>> congratulations for what you are doing!
>>
>> I am tring to construct a mesh around an object. It is a 2D unstructured
>> mesh. The file .geo is in attachement and works well.
>> First question: Because I impose a number of points on the object, is the
>> caracteristic mesh size "poids1" working anymore? I mean is the transfinite
>> command interacting with the caracteristic mesh size command or is it
>> erasing it?
>>
>> Now I would like to make a refinement around line number 104 (x~=0.6).  See:
>> Line(104).
>> I can not find the best way to do it. I have tried:
>> i- "transfinite command" but "the software" doesn't take care of what is
>> writting. See: Transfinite Line (104)
>> ii- "attractor command" but on the "forum on internet" you say that it is
>> not complety operational.
>> iii- To redefine a surface. See: Plane Surface(1001). That is to say I try
>> to refine between x=[0.5,0.7]. But with this way I have two meshes and no
>> continuity between the interfaces issued from the first mesh and the second
>> one (I mean I don't want to split my interfaces from the first mesh in two
>> lines at the connection surfaces!).
>> Thus second question is : How is the best way to do what I want: to make a
>> refinement around line number 104?
>>     
>
> Does the attached Object.geo do what you want?
>
> In modifying Obeject_GERALD.geo, I broke up the spline along the
> extrados and made the lines emanating from Point 201 have feet at
> points of the spline, then the two triangles adjoining the attractor,
> Line 104, were made Plane Surfaces, and finally the rest of the domain
> excluding these two surfaces, was made into a third Plane Surface.
>
> I too remember reading a disclaimer about Attractor, can't remember
> where, but I've found it to work well in these situations.  See also
> http://www.geuz.org/pipermail/gmsh/2011/006166.html. I didn't use
> Transfinite here.
>   

It works well. Thank you very much for your kind help. I understand 
better how the "attractor command" works now.

Best regards,

-- 
Sophie Gérald
PhD Student
http://www.onera.fr/
Tél. +331 467 33919 

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