Experimental Investigation on Sediment Erosion and Diffusion Characteristics During Coandă-Effect-Based Nodule Collection

Small-scale experiments were designed and conducted to investigate the sediment erosion and diffusion characteristics during Coandă-effect-based polymetallic nodule collection under a viscous sediment bed. A protocol for preparing artificial sediments was devised, and 3D scanning technology coupled with turbidimetry techniques was used to quantify the impacts of collector jet velocity v and bottom clearance h on sediment erosion and diffusion. The findings reveal that an increase in v and a decrease in h leads to an increase in the level of disturbance, with a linear trend for some of the indicators, but there are also areas of insensitivity to change. Spatially, sediment particles show a clear tendency of localized aggregation, while temporally, sediment turbidity currents show a trend of short-term fluctuations and long-term stable changes. As a result, the traditional sediment plume monitoring system has been refined, culminating in the proposal of a new monitoring model that optimally balances efficiency and economy.