Author(s): Floriana M. Renna; Umberto Fratino; Jorge Matos
Keywords: Stepped chutes; Skimming flow; Self-aerated flow; Air concentration; Point of inception
Abstract: Skimming flow over a stepped spillway is characterized by strong self-aeration downstream of the point of inception of air entrainment. In order to have a better understanding of the overall phenomenon of air entrainment and flow bulking, the main features of the self-aerated flow need to be evaluated. An experimental study has been carried out in a large-scale stepped chute assembled at the National Laboratory of Civil, Lisbon, in order to collect new air concentration data in skimming flows. In the present paper it is shown that some existing analytical models for predicting the air concentration distribution, as well as the development of the mean air concentration down the chute, compare fairly well with the experimental data.