Hydraulic analyses of stepped spillway flow

Abstract

Stepped spillways have been often used in RCC dams over the past twenty years, due to their efficiency in converting mechanical energy into heat and compliance with the technology and construction of RCC dams. Main characteristics of the prismatic stepped spillway with skimming flow can be described by empirical relationships. Scale model studies afford reliable assessment of the flow characteristics, particularly of the residual energy, if the scale effects are minimized. The measurement of flow characteristics is complex, due to the air-water flow mixture. It is expected that numerical modeling, with proper calibration and verification, will become an efficient tool for the stepped spillway design.

Stepenasti brzotoci se u poslednjih dvadesetak godina veoma često koriste kod brana od valjanog betona (RCC). To je posledica njihove efikasnost u pretvaranju mehaničke energije u toplotnu i usklađenosti sa tehnologijom građenja RCC brana. Glavne karakteristike strujanja na stepenastom prizmatičnom brzotoku, pri klizećem toku, mogu se odrediti empirijskim jednačinama. Hidraulička modelska ispitivanja mogu dati pouzdanu procenu hidrauličkih veličina, posebno preostale energije vode, iako je strujanje mešavine vode i vazduha složeno, a na rezultate utiču efekti razmere. Može se očekivati da će se u budućnosti i numerički modeli efikasno koristiti za ispitivanja stepenastih brzotoka, uz pažljivu kalibraciju i verifikaciju.