Analyzing Water and Sediment Flow Patterns in Circular Forebays of Sediment-Laden Rivers

Abstract

In the circular forebay of sediment-laden rivers, adverse flow patterns such as vortices emerge, leading to substantial sediment accumulation along the sidewalls of the diversion channel and in the forebay. This sediment accumulation significantly impacts the operational efficiency of water pumps. To address these challenges, a combination of numerical simulations and engineering experiments was employed to reveal the factors contributing to the development of these patterns. Based on these findings, seven distinct flow rates and operating conditions were introduced to obtain the optimal inlet flow rate and increase the sustainability of engineering use. The findings revealed that the different inlet flow rates exert varying influences on the flow patterns in the circular forebay, leading to changes in sediment levels in both the forebay and diversion channels. Following comprehensive comparison, Scheme 6 was identified as the optimal flow rate scheme. In this scheme, the flow uniformity, deviation angle, ratio of the vortex reduction area parameter, and rate of vortex area reduction in sections z1−3 were markedly enhanced. The effectiveness of this scheme was validated through rigorous numerical simulations and engineering experiments, thereby offering indispensable theoretical insights into the operation of pumping stations in circular forebays.