where N0 is an arbitrary user-specified flux expression. For example,
N0 can represent a flux due to chemical reactions, or a phase change. A positive
N0 implies that the concentration inside the fracture increases.
The available options are General inward flux and
External convection. If the latter is chosen, define a
Mass transfer coefficient and a
Bulk concentration. Specify the flux of each species individually. To use another boundary condition for a specific species, make sure that the check box for the mass fraction of that species is unchecked.
