Several tests suggest that the diffusion_mass_flux output may be incorrect. When advection is turned off (water_flux = 0), transport should be governed entirely by diffusion. While tracer concentrations are observed at downstream locations — indicating that diffusion is indeed occurring — the observed diffusion_mass_flux remains zero. This inconsistency suggests that the flux may not be computed or extracted correctly.
Several tests suggest that the
diffusion_mass_fluxoutput may be incorrect. When advection is turned off (water_flux = 0), transport should be governed entirely by diffusion. While tracer concentrations are observed at downstream locations — indicating that diffusion is indeed occurring — the observeddiffusion_mass_fluxremains zero. This inconsistency suggests that the flux may not be computed or extracted correctly.