Dynamic Interaction of Twin Particle Clouds in Stagnant Water

Abstract

AbstractA series of laboratory experiments was conducted to investigate the interactions of particles in two adjacent particle clouds vertically released in stagnant water. In order to understand the effects of controlling parameters in particle interactions between two particle clouds, the effects of sand mass and the distance between two nozzles of the adjacent particle clouds (source separation distance) were studied. By diving the mass of sand particles into two equal masses and releasing them through two adjacent nozzles, the overall sand concentration decreased due to the attenuation of the cloud length. The length, width, and frontal velocity of twin particle clouds were measured and the results were compared with the corresponding single particle cloud with the same sand mass and nozzle diameter. The entrainment coefficients of twin particle clouds with different aspect ratios and source separation distances were calculated and the results were compared with the corresponding single particle clouds. The results showed that the maximum cloud aspect ratio in single particle clouds decreased between 20 and 40% when the same particles were released through two adjacent nozzles. The reduction of aspect ratio in twin particles decreases the tendency of pollution distribution in aquatic environment. The velocity field inside twin particle clouds during cloud evolution was measured with Particle Image Velocimetry (PIV) technique. The PIV results showed that the ambient water enters the particle cloud from the sides and the space between two adjacent particle clouds.