An Efficient 1D Hybrid Numerical Model for Bed Morphology Calculations in Alluvial Channels

This paper presents a hybrid numerical model for morphodynamic flow simulation in open channels. For this purpose, a deviatoric version of the Saint Venant’s equations is solved using the Beam and Warming implicit finite difference scheme. The Exner sediment continuity equation is solved using a simple finite difference scheme. The hydrodynamic and the sediment transport models are then coupled using the semicoupled approach. Due to the use of the deviatoric version of the governing equations, the model can efficiently handle the undulated river bed. Secondly, the present model can also use larger time step due to its implicit nature. Moreover, the implicit scheme is also iteration free and can smoothly handle transcritical flow regime. The model is tested in several test cases with bed slopes ranging from −0.244 to 0.086. The results obtained are compared with results of some existing models and found to be capable of handling varied situations with sufficiently high time steps.