ABSTRACT

A numerical model has been established for simulating bed aggregation in alluvial channels. In this regard, transient gradually varied flow equations pertaining to sediment transport suitable for wide channels/rivers are chosen. For descritization of equations, explicit and hybrid schemes, based on Taylor-Galekin concept of Finite Element approach, have been developed. Numerical computations were made for spatial convergence and efficiency. From these numerical experiments, the hybrid finite element scheme using two-step predictor-corrector method found the stable solution. The validity of the model has been assessed comparing predicted transient bed profiles with experimental data and the analytical solution; good agreement is obtained. The model was also tested for various sediment supply rates at upstream; the computed results show variation in bed aggradations, which are directly proportional to amount of injected sediment load at the upstream. The numerically computed bed level proves more touching with the results of Bhallamudi and Chaudhry’s (1991) model, which reveals that the present hybrid finite element scheme is stable and accurate.