The motion of particle clouds(i.e.,sediment clouds)usually can be found in engineering applications such as wastewater discharge,land reclamation,and marine bed capping.In this paper,a series of laboratory tests are conducted on coral sand to investigate the shape feature of the single particle and the mixing processes of the coral sand particle clouds.The shape of coral sand particle is measured and quantified.The experimental results demonstrate that the shape of coral sand particles tends to be spherical as the particle size decreases,and empirical equations were established to explain the variation of D50 andffs,so of coral sand.Compared with the silica sand,the evolution of the coral sand particle cloud still experiences three stages,but the threshold for the Reynolds number of particle clouds entering the next stage changes.Further,the normalized axial distance of the coral sand particle clouds is 58％smaller.The frontal velocity exhibits similar varying tendency for the coral sand particle cloud.Considering the difference in shape between coral sand particles and silica sand particles,a semi-empirical formula was proposed based on the original silica sand prediction formula by adding the shape factor and the experimental data of 122 um≤D50≤842 pm.It can predict the frontal velocity of the coral sand particle clouds.

CHEN Jie;YAO Zhen;JIANG Chang-bo;WU Zhi-yuan;DENG Bin;LONG Yuan-nan;BIAN Cheng

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

中国海洋工程（英文版）

[1]CHEN Jie;YAO Zhen;JIANG Chang-bo;WU Zhi-yuan;DENG Bin;LONG Yuan-nan;BIAN Cheng-.Experiment Study of the Evolution of Coral Sand Particle Clouds in Water)[J].中国海洋工程（英文版）,2022(05):720-733

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