Particle Entrainment from a Rectangular Cavity in Open-Channel Flows

Abstract

Past researchers have studied particle entrainment on a flat-bed and the flow fields in a rectangular cavity without considering particle entrainment. However, particle entrainment from a rectangular cavity, which hitherto had rarely been studied, is the focus of this study. The entrainment phenomenon is investigated by using a frequentist probabilistic approach. The spatial and temporal variations of the cavity and flat-bed flow fields are compared using measurements from the particle image velocimetry and acoustic doppler velocimetry techniques. The particle’s motion from the cavity is superimposed onto the measured flow field to examine the mechanism of entrainment. The results show that particle entrainment from a cavity subjected to the same approach flow takes place over a wide range of the Shields parameter and in highly variable time duration. Additionally, the particle’s upward trajectory reveals how the highly turbulent and unsteady flow affects the entrainment process, resulting in the observed stochastic trend.