Dear Wolfgan, Probably I understood how to set Dirichlet boundary condition using interpolate_boundary_values() and specifying argument boundary_id(but not tried it yet). But how about Neumann boundary condition? As I understand, using custom boundary_id on boundary cell, and with any specification by interpolate_boundary_values() will give me Neumman with zero flux, but I can't figure out how to set nonzero flux.
PS: A little out of topic question. Even if I solved my equation and have the *solution* vector, but I can't figure out how to "access" it like to function f(x,y)? It is done somehow by FEValue class? Regards, Oleg Kmechak On Wednesday, 28 November 2018 05:45:41 UTC+1, Wolfgang Bangerth wrote: > > On 11/27/18 6:56 PM, Oleg Kmechak wrote: > > > > But you can't set boundary indicators on faces > > that are not actually at the boundary. > > > > > > You mean that I can't set Dirichlet Conditions on such structure as the > tree > > above? > > Cos this feature is critical for my work > > What I'm saying is that you can't set boundary indicators on faces between > two > cells (i.e., on *interior* faces). That's because these are not actually > on > the *boundary*. > > If you want to set conditions on degrees of freedom in the interior of the > domain, you need a different approach. The easiest way is to make sure > that > the faces where you want to set boundary conditions are really at the > boundary > -- i.e., these faces have exactly one adjacent cell; but you can have two > faces each bounding one cell at the physically same location: these are > then > boundary faces. > > Other approaches are to copy the logic of interpolate_boundary_values() > and > make it work on interior faces that you mark through some other approach. > > Best > W. > > -- > ------------------------------------------------------------------------ > Wolfgang Bangerth email: bang...@colostate.edu > <javascript:> > www: http://www.math.colostate.edu/~bangerth/ > > -- The deal.II project is located at http://www.dealii.org/ For mailing list/forum options, see https://groups.google.com/d/forum/dealii?hl=en --- You received this message because you are subscribed to the Google Groups "deal.II User Group" group. To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
