Three-dimensional Flow Structure Inside the Cavity of a Non-Aerated Stepped Chute

Accurate energy dissipation estimation and improved knowledge on stepped spillways and stepped revetments flow structure may allow safer design of hydraulic and coastal structures. In this study, an ADV Vectrino Profiler has been used to obtain dense observations of the three-dimensional flow structure occurring inside a cavity of 20 cm to 10 cm (length to height) for four flow cases. The obtained friction factors show a strong inverse dependence on the Reynolds number. The displacement length also shows a reduction with increasing Reynolds number, which may indicate that the flow “feels” the cavity more at smaller streamwise velocities. Streamwise and normalwise velocities reveal both a turbulent boundary layer type of flow (upper flow region) and a jet impact and recirculation inside of the cavity. Spanwise median velocities allowed insight on the uncertainty levels of the ADV Vectrino Profiler measurements.