Abstract
The chute aerator of a spillway is a structure in such a sense that air is, in the intense emulsification, entrained into the high-velocity water flow. Correctly predicting the air entrainment and two-phase flow pattern at the aerator would contribute to reliable spillway operation. Based on experimental data, 2D numerical simulations are preformed to predict streamwise air concentrations in the aerated flow, in which a two-fluid model is used. Depending on the air bubble size, relatively good agreement is seen with the experiments in the air cavity zone. The simulations give rise to higher air concentration downstream of the cavity, which is presumably due to underestimation of the interfacial forces in the two-fluid model.
Highlights
Spillways are important hydraulic structures for dam safety
If the water flow velocity exceeds, for example, 20 m/s and the cavitation index drops below a certain limit, damage may occur due to cavitation in the chute bottom, which affects the safety of the spillway [1]
To model the air-water flow at an aerator is a challenging issue, especially if the water flow velocity is high, which is the case in most spillway installations
Summary
If the water flow velocity exceeds, for example, 20 m/s and the cavitation index drops below a certain limit, damage may occur due to cavitation in the chute bottom, which affects the safety of the spillway [1]. Protecting spillways from cavitation damage is a primary goal of engineering design. An aerator entrains air into high-speed flow, alleviates the negative pressure near the chute bottom, and avoids the risk of cavitation. Kramer and Hager [9] examined, through experiments, flow velocity, air concentration, and air bubble size distributions; they concluded that the bubble rise velocity in chute flows depends on the Froude number. Pfister and Hager [7, 8] analyzed the effects of geometrical parameters on streamwise distributions of air concentration downstream of aerators
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
