A Study of Air Entrainment: Application to Spillway Design = Etude des Phenomenes d'Entrainement d'Air: Application aux Evacuateurs de Crues

Cavitation erosion damage to spillway surfaces may be prevented with the use of aeration devices, called aerators. These serve to introduce air in the layers close to the channel bottom in order to redue the cavitation damage. The performances of spillway aerator are studied with data on a steep spillway model and high velocities from 4 m/s to 15 m/s. Air concentration and velocity profiles at various cross-sections above and downstream of the aerator are presented and analysed. They provide a better understanding of the air entrainment processes above a bottom aerator. A new analysis of the flow downstream of an aerator is presented and this contributes to a new method for the determination of aerator spacing.