Author(s): Chenwei Zhao

Linked Author(s): Chenwei Zhao

Keywords: Bedload saltation; Large-eddy simulation; Turbulent; Rough channel flow; Shape factor;

Abstract: Saltating mode of sand particle transport, compared with rolling and sliding modes, was regarded as the most dominant mechanism of bedload transport in a fluvial stream by earlier investigations. In this paper, considering various shape factors of natural sediments, a numerical simulation of sediment particle saltation by streamflow are presented. At first, a roughness closure method is employed to generate a rough sediment bed. The large-eddy simulation (LES) is used to simulate the turbulent channel flow condition. The Newton’s second law and Euler’s equation are applied to calculate the forces and torques acting on the saltating particles respectively to determine their state of translational and rotational motion. Then, the mathematical model was validated by the experimental data from Niño and García (1998a). The computational saltation statistics for different shaped particles such as saltation lengths, heights, streamwise velocities, angular velocities and resting time are analyzed and compared. Finally, bedload transport rates are estimated as the product of the particle velocity, the saltation height and the bedload concentration which agreed well with previous classical formulas and experimental data.

DOI: https://doi.org/10.3850/38WC092019-0455

Year: 2019