NUMERICAL SIMULATION AND FACTOR ANALYSIS OF FLUSHING RIVER MOUTH BAR

摘要

A 2D river morphology model with a curvilinear grid is developed to simulate the flushing river mouth bar which occurred in the Ara River in July 2004. In the hydrodynamic model, the 2D free surface flow is calculated by Saint Venant equations which are solved by an implicit finite difference technique and the ADI method. In the morphological model, the Van Rijn's model is used to evaluate suspended and bed load sediment transport. The helical flow and the transverse bed slope modify the bed load sediment transport. The bed level change is computed by a sediment continuity equation with the bank erosion model. This model is validated by making a comparison with the observations of water level variations and the riverbed topography at the mouth. A factor analysis is conducted to evaluate the effects of discharge, tidal levels, and grain size. The result shows that the differences of sea elevation and peak discharge have significant effects on the process of morphological change at the river mouth.