Stepped spillways with aerators: hydrodynamic pressures and air entrainment

ABSTRACT The possibility of damage due to the phenomenon cavitation leads design stepped spillways considering maximum specific discharges 15 30 m2/s, a limit considerably lower than that practiced on smooth chutes. Aerators promote insertion air in flow, allowing for increase flow rates. This work analyzes pressures vertical faces steps and entrainment coefficient through an experimental study physical model with chute angle 53.13o, installation aerators different places channel. Comparing tested conditions natural aeration, it is concluded aerator does not change magnitude minimum extreme hydrodynamic pressures, but anticipates beginning aeration. A new equation proposed estimate coefficient, as well methodology forecasting steps, both valid range 3.0 ≤ Fr 6.0.