Author(s): Giulia Garegnani; Giorgio Rosatti
Linked Author(s): Giorgio Rosatti
Keywords: No Keywords
Abstract: In unsteady flows, the uniform sediment transport is commonly described by solving the conservation equations of mass and momentum both for solid and liquid phases. If the non-uniformity of the sediment becomes relevant, a new set of equations, regarding the time and space evolution of the grain size distribution of the solid phase, must be considered. Two approaches are presented in literature. The bed material fraction (BMF) model discretizes the grain size distribution curve in a finite number of classes while the statistical moment (SM) approach, proposed by Armanini, (1992) and (1995), describes the distribution curve by means of its moments (commonly means and variance). Herein a rigorous analytical derivation of the SM equations is proposed. The two models are implemented in the case of 1D rectangular channel with unitary width and compared. Advantages, limits of the two approaches and some preliminary numerical results are herein presented.