Simplified Analytical Solution for Non-equilibrium Suspended Sediment Transport based on Two-phase Flow Theory

Suspended sediment transport has been one of the basic issues in the field of river dynamics for centuries because the erosion, transport, and deposition plays a key role in the fluvial process and engineering practices. Therefore, much effort has been made to theoretical studies on the suspended sediment transport. Suspended sediment transport, as a typical two-phase flows, has been investigated widely and deeply by using the two-phase flow theory in the recent decades. For instance, Greimann et al. (1999), Greimann and Holly (2001), Ishii and Hibiki (2006), and Zhong et al. (2011, 2014) discussed the variations of concentration and velocity in steady and uniform open channel flows. Especially, the studies by Zhong et al. (2011, 2014) and Zhang et al. (2014) analyzed the effect of particle inertia on the concentration profiles, which shows that the effect of particle inertia is significant with the increasing of concentration and particle size. However, under the non-equilibrium condition, the inertia effect has not been properly considered in theory. In this study, the simplified analytical solution for non-equilibrium suspended sediment transport in open channel flows based on the two-phase flow theory was derived. Although several simplifications were used to obtain the relation for the concentration profile, it is still valuable for the basic understanding of the non-equilibrium transport process and underlying physical mechanisms. Furthermore, comparison with the previous studies was also presented. The inertia effect on the non-equilibrium suspended sediment transport was finally discussed.