Poluição de águas subterrâneas: seleção de um modelo matemático de dispersão bidimensional

Abstract

An approach to the groundwater pollution may be done by a set of equations which includes two continuity equations, one for the mixture water and pollutant (flow equation) and other only for the pollutant (mass-transport equation), Darcy's equation and state equations for the mixture. Complex boundary conditions in practical cases may lead to the use of numerical methods to solve this set of equations, because analytical solutions are not available. However, some difficulties appear when numerical methods are applied to the mass transport equation: the numerical solution presents overshoot and numerical dispersion. In this work, several methods developed for eliminating this type of problems were analysed and compared. The comparisons were made for simplified cases (uni and bidimensional) for which there are known analytical solutions. In the sequence of the works, it was possible to select a simulation model for the pollutant transport in groundwater, whose theoretical background and numerical methods are presented. The model's performance was verified for two simple cases.