Experiment research on ski-jump energy dissipation of curved flow

This study investigates the dissipation of curved flow by applying trajectory energy dissipation to avoid increasing harmful vibration. Based on experimental study, a new type of ski-jump energy dissipater is developed with a narrowing curved dentated miter bucket for a curved spillway with super-elevation. The dissipater is able to facilitate flow diversion under mass force that successfully promotes reduction of the flow range inducing backwater while extending the length of the jet flow. The hydraulic characteristics of flow diversion, backwater and jet flow observed when using the new dissipater with a sidewall with different radius of concavity are compared with those of a curved miter bucket. Additionally, a semi-theoretical and semi-empirical approach is presented to distinguish the occurrence of backwater in the new dissipater, according to the geometric characteristics of streamline and the flow characteristics. Experiments with the new dissipater reveal that contraction of the upper bucket and the radius of concavity of the sidewall play leading roles in the phenomena of flow diversion and backwater. Therefore, an expression is deduced to calculate the criterion γ_c predicting the occurrence of backwater, by the analysis the flow on the upper bucket via the deflecting angle of the folding flow γ conveyed through an empirical expression that combines the quantities of flow and concavity sidewall radius. The outcomes of the method generally matched the results derived from experiment. The findings of this study could be used as reference in the field of hydraulic engineering of curved flow.