libmesh-users

[Libmesh-users] Face ids in gmesh and libMesh

[Nikrouz <nik...@gm...>]

Dear all libMesh users,

I have produced a 3D msh file by Gmesh but I do not define any group 
surface in Gmesh.

In order to identify different faces, is there any class or method in 
libMesh or it is neccsary to define id for msh file in gmesh?

The mentioned faces will be used for boundary conditions.

Thanks everybody for your help and guidance,

Re: [Libmesh-users] Face ids in gmesh and libMesh

[John P. <jwp...@gm...>]

On Mon, Apr 29, 2019 at 6:02 PM Nikrouz <nik...@gm...> wrote:

> Dear all libMesh users,
>
> I have produced a 3D msh file by Gmesh but I do not define any group
> surface in Gmesh.
>
> In order to identify different faces, is there any class or method in
> libMesh or it is neccsary to define id for msh file in gmesh?
>
> The mentioned faces will be used for boundary conditions.
>

Boundary conditions are specified by "Physical" groups in the gmsh input
file. libMesh reads sections like the following:

$PhysicalNames
5
1 2 "left"
1 3 "right"
1 4 "top"
1 5 "bottom"
$EndPhysicalNames

and converts them into named sidesets with the ids specified.

You might also find this tutorial helpful:
https://albertsk.files.wordpress.com/2012/12/gmsh_tutorial.pdf

-- 
John