The significance of Compound Channel hydraulics in spatial and temporal distributions of pollutant transport using Crank- Nicolson scheme

A numerical investigation of pollutant transport in compound channels is carried out using POLLUTE1, a 2D modeling approach for floodplain flow hydrodynamics linking with a numerical solution of the advection-dispersion equation using Crank- Nicolson Scheme. The temporal and spatial variations of pollutant concentration were then established by applying the calculated hydraulic parameters. The cases considered correspond to rivers with low and high bed slopes of symmetrical compound channels and homogeneous and non-homogeneous roughness boundaries that so often been proposed elsewhere. The results indicate that at the early stages of overbank flow treating the flow hydrodynamics in compound river channels in low bed slopes and non-homogeneous roughness boundaries may exhibit very different temporal pollutant distribution along the channels when compared with the results ignoring any interaction effects between the floodplain and the main channel flows. Furtheremore, the selection of the numerical scheme of Crank-Nicolson revealed more intreraction than that of implicit scheme.

کلیدواژه ها:

compound channels ، pollutant ، POLLUTE1 ، non-homogeneous roughness ، Crank-Nicolson Scheme