MODELING NON-UNIFORM-SEDIMENT FLUVIAL PROCESS BY CHARACTERISTICS METHOD

This paper presents a numerical model based on a multimode characteris tics method for fully coupled simulation of water and sediment movemen t in mobile-bed alluvial channels with nonuniform bed materials. Along with the characteristics, the temporal evolutions of flow depth and v elocity, bed elevation, and bed-material composition of a well-defined river reach with proper boundary conditions can be simultaneously det ermined. From the results of the test runs, the proposed model provide s useful information about the interactions among disturbance waves of different orders of magnitude and their influence on the formation of flow field, bed topography, and bed-material composition. Such inform ation cannot be easily obtained from finite-difference methods.