Closed requested to merge prepare-shallowwater-viscousflux-for-sediment into master
Since the shallow water viscous momentum flux is only implemented for 2D
depth averaged models, the
ShallowwaterViscousFlux checks if the number
of equations is equal to three. Unfortunately, this prevents the use of
the viscous flux for models which couple shallow water flow and sediment
transport, because these models have more equations.