Experimental Investigation of Pier Waves on Gated Chute Spillways

Document Type : Research Article

Authors

1 M.Sc. Student, Civil Engineering Department, K.N. Toosi University of Technology

2 Associate Professor, Civil Engineering Department, K.N. Toosi University of Technology

Abstract

Spillways are the most important structures of high dams which are responsible for the discharge of the excessive flood from the reservoir. Although many studies have been made to determine the flow characteristics over these structures, little information is available on the supercritical flow downstream of chutes piers and their effects on flow characteristics. Flow behind chute piers generate a wavy flow known as rooster tail. Due to the flow interaction with the chutes piers, three kinds of standing waves just downstream of the pier, on the middle of the chute and on the sidewalls generate. This phenomenon affects the flow domain and its hydraulic characteristics along the chute spillway. The height of the waves increases downstream, where they hit the chute walls and reflect again into the flow to interact together again. The process repeated and intensified downstream in a lozenge shape. The height of these waves can be more than twice the water depth, and thus, run over the sidewalls. This is important for the design of chute walls in chute spillways with control gates. In this study, experimental formation of rooster tail and its behavior along the chute and its reduction measures are presented. Experiments were conducted on a scaled physical model of Kheirabad dam spillway, at Water Research Institute of Iran. It was realized that apart from the geometry of piers and chute spillway, Froude number of flow and gate opening are the main effective parameters on hydraulic performance of rooster tail formation and its development on gated spillways.

Keywords

References

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History

  • Receive Date: 15 December 2014
  • Accept Date: 15 December 2014

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