Hybrid Solutions for Multidimensional Contaminant Dispersion Models in Rivers and Channels

A hybrid analytical-numerical strategy based on the Generalized Integral Transform Technique (GITT) is used to solve steady-state multidimensional models for contaminants dispersion in rivers, streams and channels. The aim is to analyze and exploit this hybrid approach in the reduction of computational costs associated with convection-diffusion models that contain more than one space variable. The main focus of this work is the proposition of solutions for models that include variable coefficients such as variable velocity fields and turbulent diffusion coefficients along and across the river. The mathematical formulations also allow the use of arbitrarily general inlet conditions such as point, linear and plane sources. A few test cases were simulated and the models were validated both numerically and with experimental data taken from the literature. The models were implemented on the symbolic computation platform of the Mathematica system.