Author(s): Junsheng Jiang; Adrian Wing-Keung Law; Nian-Sheng Cheng
Keywords: Two-phase analysis; turbulence; sediment transport; open channel flow
Abstract: The transport of suspended sediment in open channel flows is of key interest to the area of fluvial hydraulics. Traditionally, the phenomenon is analyzed as a one-phase composite system for simplification. In reality, two separate phases of liquid and solid are present. In this study, the two-phase approach of particle group model is adopted to quantify the behavior of suspended sediment transport in open channel flows. The analysis reveals a drift current due to the gradient of turbulence fluctuation, in additional to the Fickian-type dispersion due to the concentration gradient. In the vertical direction, the resulting equation from the analysis is similar to the classical convection-diffusion equation such as the Rouse model. However, the incorporation of the additional dispersion terms predicts more accurately the sediment concentration distribution along the water depth. In the horizontal direction, the analysis shows that the mean fluid velocity is always larger than that of the sediments. The interaction between the sediment and fluid and the effects of sediment inertia are also addressed. Experiment data from the literature are used to verify the results.