LAUSR

Abstract In this study, pressure fluctuation and also the effect of entrance flow conditions on the pressure fluctuation on the bed of compound flip buckets used in the Gotvand dam in Iran are investigated experimentally. For this purpose, Pressure fluctuations on the buckets are measured in the entrance flow Froude number range of 3.5–7.5. Results show that mean of pressure decreases and pressure fluctuation increases when depth and discharge of the entrance flow increase or Froude number decreases. Furthermore, mean of pressure is maximum at the beginning and also minimum at the end of the buckets. The pressure fluctuation is maximum at the beginning and end of the buckets. In contrast, the pressure fluctuation is minimum at thalweg of the buckets. Therefore, this can be concluded that deflection of the flow streamlines is on the effect of the changing of the buckets bed and also impact of high-speed water flow at the beginning of the buckets can cause that the maximum value of mean and fluctuation of pressure occurred at the beginning of the buckets.