Implementing Nitsche's method for perfect-slip BCs with a nontrivial normal vector

[dparsons]

If what you need is a controlled flux BC on a nontrival boundary, some solutions were suggested at

Setting scalar function for BDM boundary condition with controlled flux [mixed Poisson]

I’m interested in systems with controlled flux at the boundary. As I understand the divergence-conforming elements such as BDM (or Raviart-Thomas) are a natural choice for this. Following the example of the mixed Poisson demo, the boundary condition for vector-valued function \sigma is \sigma \cdot n = g \; \mathrm{on\ } \Gamma_N so the flux (normal component) at the boundary is determined by scalar function g. What I want is a symmetric solution with the same scalar function g applied at t…

This is not using Nietsche’s method, it’s a different way to set the BC using FacetNormals.