Experimental investigation about the incipient velocity of spherical particles on a hemispherical bed surface--颗粒学报PARTICUOLOGY

Li, C., Chen, J., Jiang, C., Li, X., & Wu, Z. (2024). Experimental investigation about the incipient velocity of spherical particles on a hemispherical bed surface. Particuology, 88, 49-61. https://doi.org/10.1016/j.partic.2023.08.021

Experimental investigation about the incipient velocity of spherical particles on a hemispherical bed surface

Chuannan Li ^a, Jie Chen ^{a b c *}, Changbo Jiang ^{a b c}, Xie Li ^a, Zhiyuan Wu ^{a b c}

a School of Hydraulic and Environmental Engineering, Changsha University of Science & Technology, Changsha 410114, China
b Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province, Changsha 410114, China
c Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province, Changsha 410114, China

10.1016/j.partic.2023.08.021

Volume 88, May 2024, Pages 49-61

Received 26 June 2023, Revised 10 August 2023, Accepted 29 August 2023, Available online 20 September 2023, Version of Record 6 November 2023.

E-mail: chenjie166@163.com

Highlights

• The incipient velocity equation is conceived by the rolling instability mechanism.

• A series of 240 experiments were carried out on particle motion.

• Determination of drag and lift coefficients on the incipient velocity equation.

• Dispersive pressure will reduce the velocity by promoting particle motion.

• The particle arrangements affect particle motion.

Abstract

The sediment particles play a huge role in shaping the bed load transport. In this research, 240 water-tunnel experiments are carried out to investigate the incipient velocity of the observation particles in two particle arrangements. To accurately predict the incipient velocity of the observation particles, the equation is conceived by the rolling instability mechanism. The incipient velocity equations and experimental data are used to analyze the trend of dispersive pressure and the effect of arrangement position on velocity. We find that it is appropriate to choose the coefficient of drag as 0.261 and the coefficient of lift as 0.198 for the incipient velocity equation of spherical particles on the hemispherical bed surface. Furthermore, the dispersive pressure is closely related to the flow state, particle size, and particle arrangement, which leads to the incipient velocity of the observation particle being at a minimum when the interference particle angle is 45°. Finally, the particle spacing and the projected area changed with the arrangements, directly affecting the incipient velocity of the observed particle. The analysis of four aspects for the coefficients, dispersive pressure, different particle spacing, and projected area will facilitate the prediction of particle incipient velocity, especially on hemispherical beds.

Graphical abstract

Keywords

Hemispherical bed surface; Observed particle; Interference particle; Dispersive pressure; Incipient velocity

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