Page - 1564 - in Book of Full Papers - Symposium Hydro Engineering

STUDY ON THE HARMFUL IMPACT OF SLIT-TYPE ENERGY DISSIPATER WATER WINGS Huang Guobing1, Du Lan2, Duan Wengang3 1. Director of Hydraulic Department, CHANGJIANG RIVER SCIENTIFIC RESEARCH INSTITUTE 2. Engineer of Hydraulic Department, CHANGJIANG RIVER SCIENTIFIC RESEARCH INSTITUTE 3. Chief Engineer of Hydraulic Department, CHANGJIANG RIVER SCIENTIFIC RESEARCH INSTITUTE CHINA 1. INTRODUCTION Slit-type energy dissipaters (STED) change the trajectories of nappes by using specific flip buckets to make the flow contract transversely and extend longitudinally. The energy of flow is greatly dissipated in this progress and then the erosion of downstream channel caused by the nappe can be relieved. Because of its advantage of efficient energy dissipation effect, STED has been widely used in hydraulic projects of high water head, large discharge, and narrow river valley. The energy dissipation problems of many large scale hydraulic projects in China, such as, Longyangxia dam, Ertan dam, Shuibuya dam, and Geheyan dam are successfully solved by the application of STEDs. From the aspects of energy dissipation effect and structure safety, the water surface in the channel, the characteristics of pressure and cavitation, the shape of the nappe, and the scouring effect of downstream riverbed of STED have been studied theoretically and experimentally. Zhang and Wu (1989), Dai and Yu (1992) observed the movement and extension features of the nappe experimentally, proposed estimated formulas for the water line in contraction section and the distance of the nappe. Wu et al. empirically provided the conversion conditions of 1564