ABSTRACT
Experimental research has been conducted in two stepped spillway model chutes assembled at the National Laboratory of Civil Engineering (LNEC) - Lisbon and at the Technical University of Catalunya (UPC) – Barcelona, respectively. Experimental data on air concentration and velocity were gathered at LNEC, whereas data on the pressure field on the step faces were obtained at UPC.
In this paper, experimental data pertaining to the minimum pressure field on the vertical step faces are analysed. The main flow parameters at the onset of the boundary layer are reviewed and a new model is included for predicting the growth of the air concentration close to the pseudo-bottom. Finally, the paper outlines safety considerations against cavitation damage on stepped spillways.
