Numerical Simulation of Salinity and Pollutant Transport in Estuary by Using a Depth Averaged 2D Model

Abstract

An implicit finite volume scheme is developed to solve the depth-averaged 2-D shallow water flow equations. The computational mesh consists of rectangular cells, with quadtree technology incorporated to locally refine the mesh around structures of interest or where the topography and/or flow properties change sharply. The governing equations are solved using the SIMPLEC algorithm on non-staggered grid to handle the coupling of water level and velocity. The discretized algebraic equations are solved iteratively using the GMRES method. The model has been tested against measurement data for steady flow at T Junction channel, unsteady flow in idealized estuary, tidal flows and pollutant transport in Gironde Estuary. The model reasonably well reproduces the temporal and spatial variations of water level and current speed observed in the measurements.