Self‐Aerated Flows on Chutes and Spillways

Abstract

In open channel flows, an important design parameter is the amount of entrained air. The presence of air within the flow increases not only the bulk of the flow, but also the transfer of atmospheric gases (e.g. oxygenation). Further aeration of high‐velocity flows may prevent or reduce cavitation damage. The present paper reviews the characteristics of self‐aerated flows on spillways and chutes, including uniform flows and gradually varied flows. First, the uniform flow conditions are presented with new prototype results. Similarities with suspended‐sediment flows and extremely rough flows are developed and the interaction between air bubbles and turbulence is discussed. Then, the basic equations for gradually varied flows are developed using the same method as Wood in 1985. The results are applied to chutes and tunnel spillways and are compared with experimental data.