How to specify boundary conditions between nodes
For a static Laplace's equation problem, is it possible to specify boundary conditions for an element edge rather than just at the nodes?
- No
The best way to specify Neumann boundary conditions is to integrate (probably analytically), over the Neumann portion of the boundary, the product of the corresponding weight (test) functions and the flux per unit boundary.
There may be some code that allows specification of fluxes per unit boundaries at nodes, which are then interpolated (probably linearly) and integrated over adjacent faces, but I don't know how well this has been tested.