Roy Stogner wrote: > > On Sat, 12 Sep 2009, David Knezevic wrote: > >> Ted Kord wrote: > >>> How do I apply a Neumann B.C at an inter-element boundary? >> >> The same way as a usual Neumann BC... the only trick is that you have to >> find which internal element to apply it to. One way to do this would be >> to set the subdomain_id of elements on one side of the inter-element >> boundary to 1 and on the other side to 2, and then search for elements >> with subdomain_id = 1 that have a neighbor with subdomain_id = 2, and >> apply the Neumann BC to the appropriate side of those elements. > > The trouble with this is that you'll still have the entries in your > matrix from the shape functions which stretch between the element on > one side of the boundary and on the other. If you have a slit in your > domain on which you want to weakly impose boundary conditions, you > need to make it an actual topologically broken slit, and then it's > just another set of exterior boundaries.
I was thinking of imposing an internal flux between internal elements (e.g. as a type of forcing, but inside the domain rather than on the boundary). In that situation an "internal" Neumann condition does the job --- the variational formulation takes care of everything for you... - Dave ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
