Author(s): Gangfu Zhang; Hubert Chanson
Linked Author(s): Hubert Chanson
Keywords: Broad-crested weir; Steep stepped spillway; Physical modelling; Jet deflection
Abstract: New experiments were performed on a large-size stepped spillway facility. The operation of the broad-crested weir was characterised together with the steep (1V: 1H) stepped chute. The introduction of a small rounding at the crest’s downstream end was shown to prevent jet deflection. The hydraulics of the weir overflow was examined, and the results showed critical flow conditions (i. e. minimum specific energy) along most portions of the crest, although the pressure distributions were not always hydrostatic and the velocity profiles were not uniform. The stepped chute flow was highly aerated. The two-phase flow in the stepped chute was characterised in details. The air-water flow properties were analysed in terms of the rate of energy dissipation, showing 60%of energy dissipation rate down the first 12 steps. .