Experimental study on energy dissipation with different slope of downstream ogee spillway.

A spillway acts as a safety device in a dam, and many dam failures are due to inadequate spillway capacity or incorrect spillway design. The purpose of this research was thus to investigate the impact of varying ogee spillway surface slopes with respect to energy dissipation. The body of an ogee spillway has two profiles, one downstream and one upstream of the crest: in this study, three ogee spillway models with downstream slopes of 0.6:1 (Model A), 0.8:1 (Model B), and 1:1 (Model C) were developed. The main objective was to investigate relative energy loss, and the energy dissipation downstream of the three spillway models was thus investigated by applying different flow rates. The energy dissipation was found by evaluating the difference between the energy of the spillway structure upstream (Eo) and the energy at the beginning of the hydraulic jump (E1), For each flow condition, the available energy in the various models was calculated at the toe of the spillway, close to the end of the upstream section of the hydraulic jump. A comparison between the results obtained from the physical models of different slopes was then made to determine which model dissipated more energy. The results showed that the model with a milder slope (1:1) demonstrated higher energy dissipation than that with the steeper slope (0.6:1), with relative energy dissipation being reduced over the spillway with any increase in flow rate. [ABSTRACT FROM AUTHOR]