Modelo de transporte de sedimento para flujo no permanente con las funciones de Yang y Ackers-White.

摘要

A mathematical model is presented for studying aggradation and degradation due to base level lowering in open channels. The Saint-Venant equations for unsteady flow and the sediment continuity equations for one-dimensional flow were solved using the second-order-accurate explicit finite difference scheme of MacCormack. This algorithm was proposed by Bhallamudi and Chaudhry, (1991). The sediment transport functions of Yang and Ackers-White were introduced in this algorithm. The application of both functions is only for non-cohesive sediments. The initial condition was assumed as steady state for water and sediment flow. The equilibrium state was interrupted by increasing the sediment supply rate for aggradation and base level lowering for degradation. The model was verified with experimental data for aggradation, degradation and filling of a trench. The model produced satisfactory results and could be used to simulate geomorphic changes in alluvial channels as long as the Yang and Ackers-White functions are applicable. In some cases artificial viscosity was added to the algorithm to satisfy stability requirements.