Abstract
Energy dissipation structures play an important role in flood risk management. Many variables need to be considered for the design of these structures. Aeration has been one of the more studied phenomena over the last years, due to its influence in the performance of hydraulic structures. The purpose of the work presented in this article is to experimentally characterize the effects of aeration on boundary friction in supercritical and fully turbulent flows. The physical model used to analyze the aeration effects consists of a spillway chute 6.5 m high and a stilling basin of 10 m length and 2 m high. A pump and compressor supply the water-air mixture and are controlled at the entrance by valves and flowmeters. The ensuing channel is monitored to determine the velocity profile and air concentration of the flow into the stilling basin. The average values of both variables and Manning’s coefficient along the channel are used to determine the relation between air concentration and energy dissipation by friction. A velocity increase with greater air entrainment has been found in all scenarios since friction is the main energy dissipation mechanism in open channels flow. Finally, an equation is proposed to characterize this evolution based on the results obtained.
Highlights
Climate change impacts may compromise the security of hydraulic structures by exacerbated extreme hydrological regimes and higher flood flows
The velocity (VOut ) and concentration (COut ) profiles obtained during the experimental works
Hinze [24]Aeration considers thatthe aeration themechanisms viscous turbulent formulation considers that aeration increases the viscous turbulent dissipation. This formulation to the reduction of the velocity profile with high concentration, but it is a theoretical proposal without refers to the reduction of the velocity profile with high concentration, but it is a theoretical proposal empirical support
Summary
Climate change impacts may compromise the security of hydraulic structures by exacerbated extreme hydrological regimes and higher flood flows. It may be necessary to improve the hydraulic capacity of current dam outlets (including weirs, spillways and sluices). The purpose of this study is to quantify the influence of aeration in the efficiency of energy dissipation structures [1–3]. Our analysis is based on a physical model test where flows with different air concentration may be produced
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