On the incipient sediment suspension downstream of three-dimensional wall-mounted obstacles

Abstract

The incipient sediment suspension downstream of a thin square tab with various inclination angles was fundamentally described using experiments and theoretical arguments. Volumetric particle tracking velocimetry and particle image velocimetry were applied to measure the sediment particle distributions and wake flows under various incoming velocities and obstacle inclination angles. Results show that suspension of sediments occurred downstream of the obstacles due to the enhanced local turbulence intensities. Although the sediment volumetric fraction was mostly determined by the variation of wake turbulence kinetic energy under low inclination angles (i.e., obstacles nearly parallel to incoming flow), this was not the case under high inclination angle counterparts where distinct downward velocities dominated the wake region and suppressed the sediment suspension. This led to the decrease of sediment volumetric fraction with the growth of tab inclination at high inclination angles. Supported by flow measurements, a revised Rouse number was introduced which allows to quantitatively integrate the coupled influence of turbulence mixing load and vertical flows across various incoming velocities and inclination angles.

Sediment bed morphology in the wake of wall mounted deformable plate

“…Recent experiments on flow downstream of tabs at various inclination angles by Bhamitipadi Suresh et al [36] highlighted the coupled influence of local vertical velocity and wake turbulence intensity on sediment suspension. In addition to bed morphology for flow over a single structure, a number of studies also explored bed-load transport in canopy flows, where the bed shear stress are highly modulated by the layout and density of plants within canopy, in addition to incoming flow speed and geometry of individual plant [37][38][39][40][41][42].…”

A Coupled CFD-DEM Study on the Effect of Basset Force Aimed at the Motion of a Single Bubble

“…Multiphase flow plays a critical role in natural and industrial systems, which exists in air bubbles in the ocean [ 1 ], sediment transport in rivers [ 2 ], the pneumatic transport of solids in the mining industry [ 3 ], particle–air systems in the atmosphere [ 4 ] and carbon dioxide in methylamine of chemical engineering [ 5 ]. Its cross-discipline, richness, diversity and complexity result in the important topics of various branches of science and engineering.…”