Suspended Sediment Size and Concentration Characteristics of Particle-driven Gravity Currents

This study investigated the vertical concentration and particle size profiles of non-cohesive particle-driven gravity currents with significant settling. Laboratory experiments were conducted using a 2D lock-exchange type tank 3.7m (length) x 0.2m (depth) x 0.3m (width). Gravity currents with non-cohesive silicon carbide particles of three different median particle diameters (17, 34 and 45 μm) were considered. Using siphon rakes, suspended sediment samples from different vertical distances were collected at three different stages (early, middle, and late stages) of the current propagation. Concentrations and sediment sizes of the collected suspended sediment samples were obtained using the total suspended solid test and the laser diffraction technique, respectively. In this presentation, our findings on the vertical concentration and sediment size profiles, and their evolution as the gravity current propagates will be discussed. Our findings are of importance in understanding the propagation characteristics and numerical modeling of particle-driven gravity currents with significant settling.