A Hydraulic Analysis of Shock Wave Generation Mechanism on Flat Spillway Chutes through Physical Modeling

Muhammad Kaleem Sarwar,Hafiz Kamran Jaleel Abbasi,Muhammad Izhar Shah,Faraz Ul Haq,Rashid Farooq,Anne W M Ng,Nitin Muttil,Ijaz Ahmad,Muhammad Atiq Ur Rehman Tariq

doi:10.3390/hydrology8040186

Abstract

Shock waves are generated downstream of spillways during flood operations, which have adverse effects on spillway operations. This paper presents the physical model study of shock waves at the Mohmand Dam Spillway project, Pakistan. In this study, hydraulic analysis of shock waves was carried out to investigate its generation mechanism. Different experiments were performed to analyze the rooster tail on a flat spillway chute and to examine the factors affecting the characteristics of the rooster tail. The study results show that shock wave height is influenced by spillway chute slope, pier shape, and flow depth. Moreover, the height of the shock wave can be minimized by installing a semi-elliptical pier on the tail part of the main pier. Further modifications in the geometry of the extended tail part of the pier are recommended for the elimination of the shock wave. Based on observed data collected from the model study, an empirical equation was developed to estimate the shock wave height generated on the flat slope spillway chutes (5° to 10°).

Highlights

To study the hydraulic characteristics of shock waves on flat spillway chutes, a physTo study the hydraulic characteristics of shock waves on flat spillway chutes, a physical ical model of Mohmand Dam spillway was constructed in the model tray hall of Center model of Mohmand Dam spillway was constructed in the model tray hall of Center of of Excellence in Water Resources Engineering (CEWRE), Lahore, Pakistan
The equation presented by Xue et al (2018) was modified for estimation of the shock wave height on flat spillway chutes (5◦ to 10◦ )
A physical study was performed on a flat spillway with varying geometric parameters of pier and spillway chute slope

Summary

Introduction

Gates are mounted onto the crest of a free spillway that controls the head, discharge, reservoir volume, and reservoir level increase The addition of these gates adds some new complex issues to the hydraulic subjects [1,2,3]. According to Ansar et al [4], not all flow conditions can occur at most spillways; flow conditions at a gated spillway tend to become controlled when the gate opening Go is smaller than the critical depth yc and submerged when the tailwater depth h is greater than yc. Al-Mansori et al [5] found that, with increasing hydraulic head up to seven times that of the design head, the flow separation zone grows linearly

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Results

Conclusion