We do this in a thermal analysis code. I can send you some snippets if you like.
I plan to add an example demonstrating this using nitsches method for nonmatched boundaries, but I'd be happy to have you beat me! -Ben On May 29, 2013, at 3:45 PM, "David Knezevic" <[email protected]> wrote: > In order to model a "film resistance" thermal interface condition, I'm > using a mesh with a "crack", and I need to assemble an interface term on > the crack. > > More precisely, I have two mesh subdomains, \Omega_1 and \Omega_2, with > coincident boundaries, but which are not connected in the FE sense. Let > \Gamma denote the coincident boundary. The term on \Gamma takes the form: > > \int_\Gamma (u_1 - u_2) (v_1 - v_2) ds, > > where u_1, u_2 (resp. v_1, v_2) are the trial (resp. test) functions on > either side of \Gamma. > > This term looks much like an interface term in DG, and I've assembled it > using an approach similar to miscellaneous_ex5 (note: I'm using C0 basis > functions, but of course the solution is discontinuous across \Gamma). > > However, when I call solve, I get: > > [0]PETSC ERROR: --------------------- Error Message > ------------------------------------ > [0]PETSC ERROR: Argument out of range! > [0]PETSC ERROR: New nonzero at (203,206) caused a malloc! > > This isn't surprising since the interface term introduces new non-zeros > in the sparsity pattern. In order to make this work, it seems I just > need to: > - Augment the sparsity pattern > - Augment the send_list (for it to work in parallel) > > I see that dof_map has functionality for doing this "augmentation", so > I'm going to try those functions out. But also I was wondering if anyone > has any example code that demonstrates this, or any > comments/suggestions, in case there are any "gotchas" with this type of > thing? > > Also, if there's interest, I'd be happy to use this model problem to > make a new libMesh example, since it exercises some functionality that > may be worthwhile having in the example suite. > > David > > > ------------------------------------------------------------------------------ > Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET > Get 100% visibility into your production application - at no cost. > Code-level diagnostics for performance bottlenecks with <2% overhead > Download for free and get started troubleshooting in minutes. > http://p.sf.net/sfu/appdyn_d2d_ap1 > _______________________________________________ > Libmesh-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/libmesh-users ------------------------------------------------------------------------------ Introducing AppDynamics Lite, a free troubleshooting tool for Java/.NET Get 100% visibility into your production application - at no cost. Code-level diagnostics for performance bottlenecks with <2% overhead Download for free and get started troubleshooting in minutes. http://p.sf.net/sfu/appdyn_d2d_ap1 _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
