ABSTRACT: Rounded stepped spillway experimental results are introduced and compared with the traditional sharp spillway. A shooting flow is recognized and introduced as a transition to the skimming flow. A quick attainment of the skimming flow is observed for rounded steps. The rounded stepped spillway is characterized by a 3% increase in the rate of energy dissipation. An increase in inception length is observed for the rounded spillway conveying small discharges, which indicates more flow stability and quicker transition to skimming flow. For high velocities (high discharges), increase in the mixed air–water length, which prevents the cavitation risk damage, is observed in rounded spillway. More inception depth and less training wall height are observed for rounded spillway. Training wall height for rounded chute is found to be 20% less than the sharp spillway. Generally, the study recommends using rounded steps for initial transition steps or for the main spillway steps rather than the sharp stepped traditional configuration.
Keywords: rounded stepped spillway, sharp stepped spillway, shooting flow, skimming flow,energy dissipation, two phase flow, flow characteristics, inception point, training wall
Fonte: Canadian Journal of Civil Engineering, 2012, 39(2): 140-153, 10.1139/l11-121.
