A random displacement model of sediment transport in ice-covered alluvial channel flows

Feifei Wang; Zhiwei Li; Wenxin Huai

doi:10.1007/s11356-022-20833-7

A random displacement model of sediment transport in ice-covered alluvial channel flows

Environ Sci Pollut Res Int. 2022 Oct;29(46):70099-70113. doi: 10.1007/s11356-022-20833-7. Epub 2022 May 18.

Authors

Feifei Wang^{1

2}, Zhiwei Li¹, Wenxin Huai³

Affiliations

¹ School of Water Conservancy and Engineering, Zhengzhou University, Zhengzhou, 450001, China.
² State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China.
³ State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, 430072, China. wxhuai@whu.edu.cn.

PMID: 35583757
DOI: 10.1007/s11356-022-20833-7

Abstract

There is a need for developing efficient models to simulate the sediment transport phenomenon in ice-covered alluvial channel flows, which is essential in enriching the theory of riverbed evolution. This study establishes a random displacement model parameterized with the time-averaged streamwise velocity U(z), the sediment settling velocity ω_s(z), and the turbulent diffusion coefficient D_z(z) to calculate the suspended sediment concentration and the longitudinal dispersion coefficient for ice-covered alluvial channels. The proposed model is first validated to determine if it could be used to predict the sediment concentration profiles by comparing to limited experiments published in the literature. Results show that the simulations agree well with the measurements except for the underestimated concentration near the ice cover boundary. Once validated, the random displacement model is applied to explore the variation law of the suspended sediment concentration and the longitudinal dispersion with different sediment particle release modes. The sediment concentration and the stable value of the longitudinal dispersion coefficient for a given flow condition in the dynamic equilibrium state are not affected by the change of the particle release mode. The Fickian time required for the longitudinal dispersion coefficient converging to a constant, however, has a close relationship with the particle release mode and increases as the water depth increases.

Keywords: Fickian time; Ice-covered channel; Longitudinal dispersion; Particle release mode; Random displacement model; Suspended sediment concentration.