Modélisation numérique du transport solide en écoulement non permanent. Application à la retenue de Belley (Rhône)

Abstract

Every three years, the washing operations in the reservoirs of the Upper Rhone let a big amount of sediment flowing downstream. Our simulation aims to describe the mixture flow in the reservoir of Belley. The model encompasses a 16 millions m 3 water volume, and a 17 km long stretch of the Rhone and derivation canal, situated upstream of the hydroelectric plant of Belley. The stretch is divided by a hundred transsects. The incoming flow is laden with very fine sediment (about 10 µm mean diameter). The used equations are the St-Venant equations, two sediment mass conservation equations in the waterstream and in the bed-stream, the sediment exchange between waterstream/bedstream equation, and the Van Rijn equations for solid discharge in equilibrium conditions. The rate of solid output volume on input volume determined by the simulation is found in accordance with in-site measures during washing operations.