Experimental investigation of a single coarse particle settling in a laterally vibrating riser

Abstract

During the transportation of ores from the deep seabed to the surface via lifting risers, vibrations induced by ocean currents and waves can exert an effect on the movement characteristics of ores inside, such as vertical drag, lateral carrying, and collisions between the ore particle and inner wall of the riser. To investigate the impact of riser vibration on the ore motion, experiments were conducted focusing on the behavior of a single ore particle settling in a laterally vibrating riser. Experimental results show that as the riser’s vibration frequency and amplitude increase, the amplitude of particle’s velocity in the vibration direction increases, while the mean value of settling velocity decreases, accompanied by larger settling velocity fluctuations. Particle-wall collisions alter the phase relationship, shifting the particle’s lateral velocity from trailing to leading that of the riser. These collisions further reduce the mean settling velocity. Additionally, an increase in the diameter ratio rises the average of settling velocity and reduces its fluctuation amplitude.