Author(s): M. Iervolino; A. Leopardi; A. Vacca
Linked Author(s): Angelo Leopardi
Keywords: River hydraulics; Bed load transport; Four equation models; Critical state; Boundary conditions
Abstract: The analysis of morphological river processes is usually performed using a sediment transport uniform flow model, even in unsteady flow conditions, assuming then that instantaneous equilibrium is attained in bedload transport. Many researchers have proposed non-uniform models aiming to remove the local equilibrium hypothesis. In the present note, the study of the characteristic curves associated to non-equilibrium models is carried out. It is shown that, as in the classical St. Venant equations, nonequilibrium models allow the occurence of a vanishing charachteristic slope, or celerity so defining a critical state. The appropriate boundary conditions are also discussed.
Year: 2003