舌形挑流鼻坎水力特性研究

基于拱坝表孔泄洪的水槽实验，分析了舌形挑坎曲率和挑角的变化对水流横向扩散及下游水垫塘底板时均压力的影响。在不同泄流量和下游水深条件下，对不同曲率和挑角的舌形挑坎以及常规挑坎进行了比较研究。结果表明，水流经过舌形挑坎时流态稳定，水舌横向扩散明显。在挑坎末端高程相同的条件下，下泄流量较小时，曲率和挑角越大，水舌单宽流量的横向分布越均匀，水垫塘底板最大时均压力越小；大泄流量时，曲率和挑角不宜过大，以保证水舌扩散效果。

Research on Hydraulic Characteristics of Flip Bucket with Tougue-type

Based on a flume experiment, the influence of the curvature change and the jet-trajectory angle change on the transversal diffusion and time-average pressure in the plunge pool are analysed. The result shows, the flow regime is steady and the nappe's transversal diffusion is distinct when the water passes through the flip bucket with tongue-type. When the water discharge is small, the larger the curvature and the jet-trajectory angle, the smaller the time-average pressure in the plunge pool. When the water discharge is large, the curvature and the jet-trajectory angle should not be too big in order to assure the diffusibility.