Caractéristiques diphasiques des écoulements sur les coursiers en marches d'escalier

Two-Phase Flow Properties of Stepped Spillway Flows

Professeur en Mécanique des Fluides, Hydraulique et Sciences de l'Environnement Department of Civil Engineering, The University of Queensland, Brisbane QLD 4072, Australie

Abstract

Stepped cascades and spillways have been used for more than 3,500 years. The recent regain of interest for the stepped chute design is associated with the introduction of new construction techniques, the development of new design techniques and newer applications. Stepped chute flows are characterised by significant free-surface aeration that cannot be neglected. Two-phase flow measurements were conducted in a large-size model (h =0.10 m, α = 22^o). Experimental observations demonstrate the existence of a transition flow regime for a relatively wide range of flow rates. Detailed air-water flow measurements were conducted for both skimming flows and transition flows. Skimming flows exhibit gradual variations of the air-water flow properties, whereas transition flows are characterised by rapid flow redistributions between adjacent steps.