A Concise Method to Predict the Mean Dynamic Pressure on a Plunge Pool Slab

Maolin Zhou,Xin Li,Weilin Xu,Jianmin Zhang

doi:10.3390/e24010045

Abstract

Hydrodynamic pressure exerted on a plunge pool slab by jet impingement is of high interest in high dam projects. The present study experimentally investigated the characteristics of pressure induced by a jet through a constant width flip bucket (CFB) and a slit flip bucket (SFB). A pressurized plane pipe was employed in the flume experiments to control the inlet velocities in the flip buckets. A concise method is proposed to predict the mean dynamic pressure field. Its implementation is summarized as follows: First, the position of the pressure field is determined by the trajectories of free jets, and to calculate its trajectories, an equation based on parabolic trajectory theory is used; second, the maximum mean dynamic pressure is obtained through dimensional analysis, and then the pressure field is established by applying the law of Gaussian distribution. Those steps are integrated into a concise computing procedure by using some easy-to-obtain parameters. Some key parameters, such as takeoff velocity coefficient, takeoff angle coefficient, and the parameter , are also investigated in this paper. The formulas of these coefficients are obtained by fitting the experimental data. Using the proposed method, the easy-to-obtain geometric parameters and initial hydraulic conditions can be used to calculate the maximum mean dynamic pressure on the slab. A comparison between experimental data and calculated results confirmed the practicability of this model. These research results provide a reference for hydraulic applications.

Highlights

Hydropower projects commonly utilize flip buckets to transfer stormwater from high elevations to plunge pools, e.g., the Mossyrock Dam in Washington State, USA [1], and the Jinping-I arch Dam in Sichuan, China [2]
Impingement jets have different properties depending on the shape of free jets, and impingement jets exert a dynamic pressure on the slab of the plunge pool
The experimental data were measured by pressure sensors that were placed on the central line of the plunge pool slab.In the constant width flip bucket (CFB) case, since the jet flow has a more concentrated cross-section, pressure distribution along the streamwise direction is more concentrated and its distribution is more Gaussian

Summary

Introduction

Hydropower projects commonly utilize flip buckets to transfer stormwater from high elevations to plunge pools, e.g., the Mossyrock Dam in Washington State, USA [1], and the Jinping-I arch Dam in Sichuan, China [2]. A thorough understanding and accurate prediction of the dynamic pressure on plunge pool slabs are essential in the design of high-elevation dams. Impingement jets have different properties depending on the shape of free jets, and impingement jets exert a dynamic pressure on the slab of the plunge pool. Their relationships are significant for engineering design in high-elevation dam projects. It is expected that for predicting dynamic pressure on plunge pool slabs, two particular aspects should be carefully considered:

Methods

Findings

Discussion

Conclusion