Stepped spillway flow: Comparison of numerical and scale models

Budo Zindović,Ljubodrag Savić,Nikola Mladenović,Radomir Kapor

doi:10.5937/fmet1403218z

Abstract

This paper deals with flow modelling of the stepped spillway for the Bogovina dam. The analysis was conducted using three approaches: scalemodelling, empirical equations and numerical modelling. An acceptable agreement was achieved between the empirical equations and the numerical model results, while both of them exhibit considerable differences when compared to scale-model. These discrepancies can be contributed to the difficulties in modelling the process of air-entrainment. Since air-entrainment is important for providing good estimates, existing empirical equations as well as numerical models require further improvements.

Highlights

In the last three decades, stepped spillways have become common overflow structures for rollercompacted concrete (RCC) dams
Hydraulic characteristics of stepped spillways can be assessed in various ways: by using the empirical equations, scale modelling, and numerical modelling
The results obtained from the scale model, empirical equations [14] and numerical model Ansys Fluent are compared for the design flow-rate of Q = 372 m3/s

Summary

Introduction

In the last three decades, stepped spillways have become common overflow structures for rollercompacted concrete (RCC) dams. The steps have significant influence on the energy dissipation along the spillway and reduce the size and the cost of the stilling basin. Low cost, combined with good energy dissipation make RCC dams a superior alternative to traditional concrete gravity dams with smooth spillways. Hydraulic characteristics of stepped spillways can be assessed in various ways: by using the empirical equations (during the preliminary design process), scale modelling, and numerical modelling (in the final design process). These three approaches are applied to the spillway of the ‘Bogovina’ dam

Methods

Results

Conclusion