|
The AD module is based on the one-dimensional equation of conservation of mass of a dissolved or suspended material (e.g., salt or cohesive
sediments). The behavior of conservative materials which decay linearly can be simulated. The module requires output from the hydrodynamic module, in space and time, of discharge and water level, cross-sectional
area and hydraulic radius.
The advection-dispersion equation is solved numerically using an implicit finite difference scheme which has negligible numerical dispersion.
Concentration profiles with very steep fronts can be simulated accurately.
 The module includes a description of the erosion and
deposition of cohesive sediment. Erosion and deposition are modeled as source/sink terms in the advection-dispersion equation. Whereas the erosion rate depends on the local
hydraulic conditions, the deposition rate depends also on the concentration of suspended sediment.
It is also possible to simulate non-cohesive sediments with the AD module. Here the transport of the suspended
sediment is described with the advection-dispersion equation, and the erosion and deposition terms are described by conventional sediment transport formulations.
Both the Advanced Cohesive Sediment Transport Module (ASC) and the Water Quality Module (WQ) are add-on modules which require the AD module.
|
