I'm trying to apply some partial boundary conditions to the step-22 stokes problem. I can't seem to find much further help on this and when I try and implement it, it solves but solution is clearly unstable/blows up.
I am trying the basics before i impose inhomogeneous quantities, and using no normal flux on the boundary, which constrains one component, and then allow no tangential stresses either, which should constrain the other two. Can anyone spot where I'm going wrong? I'm unsure whether I'm just using a very silly test case (the same as step-22) for the conditions, or whether i'm imposing things incorrectly. I am doing: std::set<types::boundary_id> all_boundaries; all_boundaries.insert (0); VectorTools::compute_no_normal_flux_constraints (dof_handler, 0, all_boundaries, constraints); then typename FunctionMap<dim>::type tang_map; ZeroFunction<dim> tang_stress (2); tang_map[0] = &tang_stress; VectorTools::compute_nonzero_tangential_flux_constraints (dof_handler, 0, all_boundaries, tang_map, constraints); I believe these are all the conditions you need.... thanks a lot -- 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.