Document Type : Research Article
Civil Engineering Department, Sistan and Baluchastan University, Sistan and Baluchastan, Iran.
Civil Engineering Department, Isfahan University of Technology, Isfahan, Iran.
Ski-jump bucket spillway is one of the energy dissipation structures applied at downstream of spillways or bottom outlets. In this study, the effect of the convergence angle of the ski-jump bucket on the flow energy dissipation was experimentally investigated and the results were compared with the conventional bucket model. For this purpose, four convergence angles of 10, 20, 30 and 40 degrees were created using deflectors in the bucket. The effect of adding a dividing wall, in two modes of bucket splitter wall (BSW) and full separator wall (FSW), on the conventional and convergent buckets were investigated. The results showed that the flip buckets dissipated about 60 to 65 percent of their energy. At a 20-degree convergence angle, the energy dissipation of the flow increased by about 5 percent, however, at a 30-degree convergence angle, the energy dissipation decreased by about 15 percent. In general, the energy dissipation decreases by increasing the flow discharge. Adding a dividing wall to the bucket does not have a significant effect on energy dissipation, although adding a separator wall to a converged bucket eliminates the effect of reduction in the energy dissipation due to convergence of the bucket. By mounting the dividing wall on the bucket, a local disturbance is created in the flow pattern, however, the resulting loss is not significant compared to the energy dissipation caused by the jet colliding with the bottom of the stilling basin. Whereas full separator wall (FSW) divides the bucket into two parts and it doesn't cause major disruption to the flow pattern.