Turbulent pressures at the position of maximum pressure fluctuation in hydraulic jump stilling basins

Pressões turbulentas na posição de flutuação de pressão máxima em bacias de dissipação por ressalto hidráulico

ABSTRACT

Turbulent flow is responsible for a significant portion of damages and failures in dams. This paper sought to introduce novel approaches to the estimation of typical parameters used in the design of stilling basins. The standard deviations of pressure samples of 24 hydraulic jumps were analysed throughout the stilling basin longitudinal centreline, and the positions of maximum pressure fluctuation were identified. Next, mean and extreme pressures occurring at this position were calculated. Finally, these parameters were plotted against the inflow Froude number and curves were adjusted to the data. The position where maximum turbulence of undular, weak and oscillating jumps occurs varies according to the Froude number. Steady and strong jumps are more likely to induce negative pressures on the stilling basin. The findings of this paper broaden the knowledge on which regions of the stilling basin must receive special attention, and on how to minimize the chances of damages.

Keywords:
Extreme pressures estimation; Position of maximum pressure fluctuation; Hydraulic structures; Stilling basins; Hydraulic jump