Propeller Jet–Induced Suspended-Sediment Concentration

Abstract

AbstractWhen subjected to a strong swirling jet flow induced by a rotating ship’s propeller, the bed of a waterway may undergo significant changes. These changes will not only cause instability to quay structures and damage the protection work of the beds/banks of rivers and canals, but also resuspend the bed sediment. The latter likely will pollute the water column and affect the aquatic life. In this study, the propeller-jet velocity and sediment-concentration profiles downstream of a propeller are measured using an acoustic Doppler velocity profiler and a suction device, respectively. The estimates obtained by using formulas for the axial velocity and four published methods for calculating the reference near-bed concentration of suspended sediment are compared with the experimental data. Moreover, the behavior underlying the temporal and spatial variations in seabed scour and sediment suspension is also investigated. A new set of equations for estimating the sediment concentration profiles is developed...