A two-dimensional finite element drying-wetting shallow water model for rivers and estuaries

A new finite element model has been developed to simulate two-dimensional f ree surface flow in rivers and estuaries. The variables of the model are th e specific discharge and the water level. The algorithm takes into account the natural boundaries of the flow, defined by the contour lines of zero de pth, with a new approach that accepts positive and negative values for the water depth. In this way, we consider a wet or dry area when the water dept h is positive or negative respectively. A 6-node triangular element and an implicit Euler scheme are respectively used for spatial and time discretiza tion of the mathematical model. The solution procedure is based on the inex act Newton-GMRES type solver with incomplete factorization as preconditioni ng. The numerical results of the proposed approach are in good agreement wi th an analytic solution and also with the classical approach. (C) 2000 Else vier Science Ltd. All rights reserved.