Experimental Investigation of Entering Flow Effects on the Intensity of Pressure Fluctuations over Compound Flip Bucket

Flip buckets are usually placed at the end of chute spillways or outlet conduits of high dams. The projected jets from these buckets jump into plunge pools which cause the dissipation of destructive energy of plunging jets. Compound flip bucket is a special design of bucket with a non-zero degree of cross sectional slope followed by a curvature in its longitudinal direction. These structures are very suitable for restricted geometries and conditional topographies. In case of high velocity flow, separation of flow the boundary also cases the local pressure to drop and as a result the resultant fluctuations may trigger cavitations. Sever hydrodynamic pressures are also associated with the vibration of structure. Therefore, in this study the hydraulic parameters such as pressure fluctuations, pressure, velocity and depth of flow on these structures are presented. Physical chute spillways with their flip buckets models of Gotvand dam were used to check the pressure fluctuations and its variation with different hydraulic characteristic along the compound flip buckets. The Froude numbers varies in the range of 3.5 to 7.5. The results were analyzed and presented in the form of Pressure coefficient corresponding to the mean pressure (CP), which was calibrated based on the present results. The results consist of the statistical characteristics of Pressure fluctuations, its Variation of maximum and minimum dimensionless positive and negative values ( ), ( ) of pressure fluctuations along the compound flip bucket. It is hoped that the present results will help the designer of such structures.