Analysis of Hydrodynamic Pressures in the Stilling Basin of an Earth Dam

Marijana Damnjanović1, Predrag Vojt1, Danica Starinac1, Dragiša Žugić1, Radomir Kapor2, Ljubodrag Savić2

 

1 Jaroslav Černi Institute for the Development of Water Resources, Jaroslava Černog 80, Pinosava, Belgrade

2 University of Belgrade, Faculty of Civil Engineering. Bul. kralja Aleksandra 73, Belgrade

 

 

Abstract

The stilling basin is one of the most frequently used energy dissipation structures due to highly-efficient energy dissipation of the main stream through the secondary turbulent flow in thehydraulic jump roller formed within the stilling basin. An important characteristic of this type of flow is pulsating pressure, which is especially pronounced on the bottom concrete slabs, side walls, and other concrete components of the stilling basin. Hydrodynamic loads on the bottom and side walls of the stilling basin are assessed in the paper, based on pressure measurements at selected points on the physical model. Measurements were made at a large number of test points, such that a reliable distribution of hydrodynamic loading was obtained under different flow conditions.

Keywords: stilling basin, hydrodynamic load, pressure fluctuations.

 

 

Introduction

 

Dam design involves solving of the problem of the dissipation of energy accumulated in the reservoir, which is transmitted to the downstream river channel. The stilling basin, in whichthe hydraulic jump is formed, is one of the most frequently used energy dissipation structures. The stilling basin thereby converts the mechanical energy of the flow into heat,through the turbulence caused by tumultuous flow and accompanied by large pressure fluctuations.

These dynamic pressures act on the bottom and side walls of the stilling basin and can damage, raise and displace the concrete slabs of the bottom and side walls. The effect must therefore be known and addressed in the design of energy dissipation structures.

The research reported in this paper assessed hydrodynamic loads on the bottom and side walls of the stilling basin at different design discharges and for two stilling basin configurations.