[Gmsh] Problem with boundary layer on 2D flat plate

DILASSER Guillaume Guillaume.DILASSER at cea.fr
Tue Jul 19 10:19:47 CEST 2016

Dear Ashish,

The shape of the boundary layer you get is due to the fact that BoundaryLayer fields do not overwrite the 1D mesh of the edges that do not appear in Field.EdgesList. Now, in your case if you do add Lines 3 and 5 to EdgesList, it would solve your problem at the corners 1001 and 1002 but also create a layer near to edges 3 and 5 and I understand this is not what you want.

The key to get what you want is to make sure the 1D mesh on the lines orthogonal to the BoundaryLayers is compatible with it, i.e. it needs to be refined close to line 2. As it doesn’t seem really easy to do, I would suggest you don’t use Fields to implement the BoundaryLayers but rather the transfinite algorithm. The enclosed file gives you a way to do it. It will work for simple geometries like the one you proposed but for more complex surfaces you would probably need something else.

Sincerely Yours,

Guillaume DILASSER
Doctorant SACM / LEAS
CEA - Centre de Saclay - Bât.123 - PC 319c
91191 Gif sur Yvette Cedex - France -

guillaume.dilasser at cea.fr<mailto:guillaume.dilasser at cea.fr>

De : gmsh [mailto:gmsh-bounces at ace20.montefiore.ulg.ac.be] De la part de ashish bhole
Envoyé : lundi 18 juillet 2016 19:40
À : gmsh at onelab.info
Objet : [Gmsh] Problem with boundary layer on 2D flat plate

I have attached a geo script for mesh on 2D flat plate. I want to create boundary layer over flat plate without use of transfinite feature, as I want unstructured mesh outside boundary layer.

I am not able to use Boundary layer feature properly. I have commented those lines in script. Can someone help me getting boundary layer correct?
-- With Regards
Ashish Bhole
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