On Mon, 27 May 2019, Alexander Lindsay wrote:
> Does it make sense/do we have the machinery to do periodic boundary > conditions with discontinuous variables like the user below is asking for? We don't even do internal continuity with discontinuous variables; naturally we're not going to do continuity across domain boundaries. Typically if you're using a discontinuous variable you expect discontinuities, right? If you actually do try to pin the value of the variable to be exactly equal from one side of an interface to the other, you end up killing your convergence: at best you've created an effective "element" of size 2h and at worst you've screwed up consistency. If you have a mesh that matches up across a periodic boundary (as you have to for libMesh PeriodicBoundary stuff to make sense even in the C0 case), then ideally what you want to do is add interface terms to your formulation to give the same sort of weak continuity enforcement across boundary sides that you'd normally use between interior neighbors; basically instead of skipping boundary sides in that loop you check to see if they're periodic boundary sides and you use the periodic neighbor for whatever jump/flux/etc terms are in your weak equations. > Maybe this is a use case for a face-face type discretization like mortar... If you don't have a mesh that matches up perfectly across the boundary, then I think mortar methods may be the way to go. --- Roy _______________________________________________ Libmesh-users mailing list Libmesh-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/libmesh-users
