Stability Analysis of Plunge Pool Linings

Abstract: 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 framework to correctly interpret the physical phenomena and to produce suitable engineering approaches in plunge pool bottom lining design.