Re: [Libmesh-users] DG and boundary conditions

[Renato P. <re...@gm...>]

Thanks Roy.

Well, I am working with fracture creation in between mesh elements. In
this case I believe it sort of makes sense to have 'strong' BCs and
internal discontinuous DOFs being tied together by interior
penalties... (not sure though)

I was considering to duplicate the DOFs myself during topology
creation: I would add triangles sharing vertices _coordinates_ but not
vertex _references_. Then I map the neighbors and tie them together
during assembly.

Would that be sound?

Rgds,
Renato

On Wed, May 2, 2018 at 2:00 PM, Roy Stogner <roy...@ic...> wrote:
>
> On Tue, 1 May 2018, Renato Poli wrote:
>
>> Are DirichletBoundary BCs expected to work in Discontinuous Galerkin
>> (L2_LAGRANGE)?
>
>
> Nope.  And you wouldn't want them to, would you?  I'm not a DG person
> myself, but I was under the impression that you always want the
> solution to be allowed to be discontinuous at *every* element
> boundary, even the ones on the domain boundary, with Dirichlet
> conditions instead enforced weakly via boundary penalties, to avoid
> overconstraining your solution.
>
> I'd love to let users be able to do "create a boundary condition
> object and then forget" about it with DG as well as CG, but I don't
> know if there's any simple way to make that happen; the boundary terms
> are inherently formulation-dependent, aren't they?
> ---
> Roy