Experimental investigation of energy dissipation on flip buckets with triangular deflectors

Flip buckets are commonly used to discharge flow from a hydraulic structure to the downstream as ski jump when flow velocity is large. Deflectors can be used to increase the efficiency of energy dissipation by flip buckets. This wedge-shaped structure deflects a portion of the flow by splitting it on the bucket. In this study, the effect of triangular deflectors which are used continuously across the channel, on energy dissipation by a flip bucket was experimentally investigated. For this purpose, a triangular deflector with three side lengths (3, 6 and 9 cm) and seven angles equal to 12°,17°, 22°, 27°, 32°, 37° and 42° was tested under different hydraulic conditions and the results were compared with a flip bucket without a deflector. The experiments were carried out in a laboratory flume with a length of 15 m, a width of 0.3 m and a height of 0.5 m. The results indicate that the model with a deflector increased energy dissipation by 8.2 to 22.7 percent as compared to that without a deflector. Increasing the deflector angle and side length initially increased energy dissipation, but then decreased it at large angles and lengths. An optimum angle of 27° to 32° was obtained with an optimal deflector length (L) to the Reynolds number (R) ratio of 0.46. A correlation was proposed to predict energy dissipation by the flip bucket with a triangular deflector using multivariate nonlinear regression. © 2020 Indian Society for Hydraulics.