窄缝挑坎因边墙收缩形成的水翅击打岸坡,可能会对岸坡稳定构成威胁,而相关研究鲜见报道。为了揭示该消能工水翅运动规律及其形成的降雨强度在下游临岸侧的分布特性,通过建立系列物理模型,开展了窄缝挑坎收缩比和挑角与水翅特性间关系研究。结果表明:随着收缩比减小,水翅被抛射得越高,次生水翅引起的降雨分布区域位置上移、范围增大;随着挑角减小,水翅顺水流向运动轨迹变化不大,但横向扩散加剧导致降雨横向分布范围增大。在此基础上提出了次生水翅横向扩散系数的概念,可用于预测不同挑坎体型下次生水翅引起下游降雨范围的形状特征。该成果可丰富窄缝挑坎研究内容,扩大研究范围,并为其体型设计提供更全面的理论依据。

Rare research has been reported on the water-wing in slit-type bucket caused by contracted sidewall which poses a threat on bank slope stability. In this article, a physical model is setup to investigate into the relation between the type of bucket (contraction ratio β and bucket angle θ) and the characteristic of water-wing for revealing the motion law of water-wing in slit-type bucket and the distribution characteristic of rainfall intensity formed by the water-wing near downstream. Results show that along with the decreasing of contraction ratio, the water-wing is ejected higher, and at the same time, the scope of rainfall is larger and its location is closer to the outlet; whereas along with the decreasing of bucket angle, the water-wing trajectory doesn’t change obviously, but the lateral diffusion aggravates, resulting in the increase of rainfall range. On this basis, a concept of secondary water-wing lateral diffusion coefficient is proposed to predict the shape and scope of rainfall caused by secondary water-wing in different slit-type buckets. The research results could enrich the research contents of slit-type bucket, expand research range, and provide more theory foundation for design.