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

作　　者：Chuannan Li Jie Chen Changbo Jiang Xie Li Zhiyuan Wu 

机构地区：[1]School of Hydraulic and Environmental Engineering,Changsha University of Science & Technology,Changsha 410114,China [2]Key Laboratory of Dongting Lake Aquatic Eco-Environmental Control and Restoration of Hunan Province,Changsha 410114,China [3]Key Laboratory of Water-Sediment Sciences and Water Disaster Prevention of Hunan Province,Changsha 410114,China

出　　处：《Particuology》2024年第5期49-61,共13页颗粒学报（英文版）

基　　金：financially supported by the National Key Research and Development Program of China(Grant No.2021YFB2601100);the National Natural Science Foundation of China(Grant No.51839002,51979014 and 52271257);the Natural Science Foundation of Hunan Province(Grant No.2022JJ10047);the Hunan Provincial Innovation Foundation for Postgraduate(Grant No.CX20220909).

摘　　要：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.

关 键 词：Hemispherical bed surface Observed particle Interference particle Dispersive pressure Incipient velocity 

分 类 号：O35[理学—流体力学]