Hamed, What you are doing in your code resembles something similar to a Picard iteration step for the term (v, n\cdot\nabla u)
Neumann boundary values mean that you want to enforce n\cdot\nabla u=g on the boundary where g is known. Typically, you do this in a finite element approach in a weak sense and replace the normal derivative in the boundary integral you get when deriving your weak formulation. E.g., for the Poisson problem you would have -(v, \Delta u)_L^2(\Omega)=(\nabla v,\nabla u)_L^2(\Omega) - (v, n\cdot\nabla u)_L^2(\partial\Omega) = (\nabla v,\nabla u)_L^2(\Omega) - (v, g)_L^2(\partial\Omega). Answering your question: If you want to apply Neumann boundary values, you know n\cdot\nabla u=g and can ask for g(q) in much the same way it is done in step-7, i.e. NeumannFunction neumann; const double local_neumann_value = neumann.value(q_point, component) where NeumannFunction is a Function object. Best, Daniel -- 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
