Virgilio Fiorotto

In the paper, the stability of a plunge pool bottom under the impact of an impinging jet is theoretically analyzed, with reference to the mean characteristics of the flow field: pressure and velocity. In cases when the mean components are relevant in respect to the fluctuating ones, this analysis is exhausting. In other cases, a separate evaluation of the fluctuation effects in lining design is treated by means of experimental evidence. The mean dynamic pressure at the bottom depends strongly on the impingement angle, which assumes a relevant role in the design of floor protections. In plunge pools, which are confined upstream by the presence of the drop structure, the impingement angle is theoretically determined by mass balance and momentum conservation, resulting independent of the jet entrance angle at the plunge pool water surface. The theoretical results are compared with literature, experimental evidence, and numerical simulations. This highlights the capability of the proposed theoretical ...

Experimental analysis concerning supercritical flow over a dentated sill in nonsubmerged conditions and the local scour downstream of this sill is presented. In this case, the energy dissipation is incomplete so that a scour control downstream of the hydraulic structure could be required. The use of this type of dissipation device could be needed in cases where the maximum flow depth upstream of the sill must be limited to satisfy physical or structural conditions. This could happen, for instance, in the restoration of stilling basin in gravity dams and at the outlet of diversion systems. Experimental and theoretical results, useful in the design of this type of stilling basin and scour control, are presented in the paper, with an application to the case of the Molato Dam in Italy.