Modèles d'évolution de lits alluvionnaires soumis à charriage : Tri granulométrique et pavage

Alluvial river modelling: bed load, grain sorting and armouring

¹ Sogreah, B.P. 172 X, 38042 Grenoble Cedex
² Institut de mécanique de Grenoble, B.P. 53 X, 38041 Grenoble Cedex

Abstract

An unidimensional model of alluvial river is developed to take account of temporal and spatial evolutions of bed (and bed load) grain compositions. The set of equations is solved in a fully coupled manner; numerical coefficients of the implicit scheme allow to optimize the time step value. A bed load "loading law" is included in the model. Some examples derived from the general features of the "middle third" of the Rhône river make clear how the flow unsteadiness affects the bed evolutions, through grain sorting and bed armouring.