> On Tue, Jan 15, 2008 at 12:23:30AM +0100, Murtazo Nazarov wrote: >> > On Mon, Jan 14, 2008 at 08:57:34PM +0100, Murtazo Nazarov wrote: >> >> > Is there an obvious high level way to implement normal flow type >> >> > boundary conditions or symmetry type boundary conditions? >> >> > >> >> > -gideon >> >> > >> >> >> >> If you mean slip boundary condition which for normal velocity, it is >> >> already implemented and soon will be available with UNICORN. >> >> >> >> The slip with friction is also implemented. >> >> >> >> /murtazo >> > >> > How is this implemented and for which element types? Maybe it can be >> > added to DOLFIN. >> > >> >> It is implemented in the "stong" way as the Dirichlet BC. The idea is to >> put u*n = u1*n1 + u2*n2 + u3*n3 = 0, where u = (u1,u2,u3) velocity and n >> = >> (n1,n2,n3) normal to a boundary node. At the monent it works for simple >> (cylinder, cube, ...) and quite complex geometries (car), but we are >> testing it in different geometries. Then, it would be good to add it to >> DOLFIN. > > I mean how do you translate u1*n1 + u2*n2 + u3*n3 = 0 into an equation > for the degrees of freedom (which may or may not be u1, u2, u3), which > types of finite elements does this work for and how do you modify the > linear system? >
It is done for the linear system. The idea is almost the same as Dirichlet implementation, but here we change two (in 2D), three (in 3D) corresponding rows of the system. I think (I may be wrong) it has nothing to do with the types of finite elements. /murtazo _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
