Effects of Hyper-concentrated Sediment on Flow Resistance in an Open Channel with Three-dimensional Square Ribs

Abstract

The necessity to understand and predict flows that carry large suspended sediment and wash loads has become acute in river basins where significant erosion and siltation associated with hyper-concentrated flood give rise to many river problems. Mud flows, debris flows or slurries, made up of a large amount of clay and/or silt particles suspended in water, often show non-Newtonian properties but remain poorly understood concerning the impacts of their rheological properties on fully developed turbulent structure. In this paper, we experimentally investigated resistance and momentum transport of hyper-concentrated sediment laden-flow in an open channel with three-dimensional square ribs by using Particle Image Velocimetry (PIV). The results showed that rheological properties significantly dissipated the turbulent flow fluctuations over three-dimensional square ribs and augmented the flow resistance by comparison with the clear water flow.