Experimental Study of Impact Pressures on Deep Plunge Pool Floors Generated by Submerged Inclined Jets with Controlled Aeration

Abstract

Hydrodynamic pressures on a plunge pool floor due to submerged aerated jets are of interest in many engineering fields. For the present study, dynamic pressures on a deep plunge pool floor due to submerged inclined jets with forced aeration were systematically investigated. The incoming flow thickness and air concentration were controlled by a plane pressurized nozzle in a hydraulic model. The results confirmed the asymmetrical distributions of the pressures on the plunge pool floor. Both the maximum mean pressure and pressure fluctuation locations remained practically unaffected under different incoming jet conditions. The mean pressure coefficient decreased with jet aeration and increased with the relative jet thickness. The coupling effect of jet aeration and thickness on the pressure fluctuation coefficient occurred in two ways. At a small relative jet thickness, a critical threshold existed for flow air concentration in which the fluctuation pressure coefficient increased and subsequently decreased with increasing air concentration. At a large relative jet thickness, the fluctuation pressure coefficient increased throughout with increasing air concentration. In general, a combination of decreased jet thickness and enhanced jet aeration can reduce impact on the bottom floor of a deep plunge pool. These research results provide reference for air–water flow discharge design in engineering applications.