[Gmsh] Boundary layers in gmsh?

[Eric Nutsch]

Christophe and Julien,


Thanks again for the examples Christophe!  For everyone's reference
here is what I concluded:

I saw the important part to meshing the BL was getting the outside surface.
Surface Loop(1001) = {96, 45, 113, 79, 62, 130, 147, 164};  /// The
outside of the BL

To get those values you have to get the output of the extrude function.
By putting the values from the extrude in the array, I determined that
the outside surface of the BL is the first value returned from the
each extrude operation.
tmp[] = Extrude { Surface{14:28:2};  Layers{5, 0.2}; // Recombine; };
/// 14:28:2 means itterate from 14 to 28 by steps of 2
Printf("tmp[] = %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g
%g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g %g",
tmp[]);


Finally the farfied is generated by removing surface loop 1001 from
surface loop 1002 in a boolean operation:
Volume(1001) = {1002, 1001};


Thanks again,
Eric Nutsch



On Wed, Feb 24, 2010 at 4:03 AM, Christophe Geuzaine
<cgeuzaine at ulg.ac.be> wrote:
> On 24/02/10 11:26, julien hoessler wrote:
>>
>> Hi Eric,
>> If it is a flat surface or if you know where the interface would be
>> located you can just move your domain line/surface to the interface and
>> extrude it towards the outside, but otherwise I can't seem to find a way
>> to link the interface with the rest of the mesh
>
> Hi Guys - boundary layers are still a bit experimental, but the basics are
> there to connect them with other geometrical entities. Attached are two
> examples:
>
> * sphere_boundary_layer.geo shows how to connect volumes to boundary layer
> faces ;
>
> * t1_boundary_layer_connection.geo shows how you can also connect things to
> the lines or vertices created during the boundary layer generation.
>
> Retrieving the id numbers of the extruded entities can be done in a script
> the usual way (list[] = Extrude...), but as usual this only gives access to
> the ids of the "top" surface, the new volume and the "lateral" surfaces.
>
> To retrieve the ids of the new lines and the new points, you have at the
> moment to resort to the GUI (in "Tools->Options->General->General" select
> "Enable mouse hover over meshes" to see the numbers displayed at the bottom
> of the graphical window).
>
> Hope this helps,
>
> Christophe
>
>> regards
>> Julien
>> On 24 Feb 2010, at 02:03, Eric Nutsch wrote:
>>
>>> Hi,
>>>
>>>
>>> Has anyone successfully gotten an extruded boundary layer to interface
>>> with a mesh?
>>>
>>>
>>> Thanks,
>>> Eric Nutsch
>>>
>>> _______________________________________________
>>> gmsh mailing list
>>> gmsh at geuz.org
>>> http://www.geuz.org/mailman/listinfo/gmsh
>>
>> Julien Hoessler
>> PhD Student
>> Department of Aeronautics
>> Imperial College London
>>
>> Phone: +44 (0) 20759 45042
>> Email: julien.hoessler06 at imperial.ac.uk
>>
>>
>> _______________________________________________
>> gmsh mailing list
>> gmsh at geuz.org
>> http://www.geuz.org/mailman/listinfo/gmsh
>>
>>
>
>
> --
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science
> http://www.montefiore.ulg.ac.be/~geuzaine
>