高海拔地区气压环境对高速水流水舌挑距的影响

我国西部高海拔地区低气压环境对高坝建设中高速水流的水力学特性研究提出了新的挑战。高速水流水舌挑距是影响水垫塘及岸坡安全性的关键技术指标。本文采用计算流体动力学分析方法研究环境气压对水舌挑距的影响程度，建立低气压环境下水舌抛射距离的理论估算公式，为高海拔地区高速水流水舌挑距的分析提供参考。研究表明，环境气压越低，水舌挑距越远；环境气压每下降10 kPa，挑距基本呈增大约1.5%的趋势。为避免由于未考虑低气压影响水舌挑距预测偏小而导致的岸坡或水垫塘安全风险，建议在高山峡谷区水垫塘紧凑布置时应充分考虑低气压对水舌挑距的影响。

Influence of low atmospheric pressure on trajectory distance of high velocity jet nappes at high altitude

Low atmospheric pressure in the high altitude areas of Western China presents a new challenge to studies of the hydraulics of high speed flow in high dam construction. The trajectory distance of high speed jet nappes is a key technical parameter for safety design of plunge pools and bank slopes. This paper examines the influence of atmospheric pressure on the nappe trajectory distance using CFD analysis and develops an analytical formula for calculation of the distance under the condition of low atmospheric pressure in high altitude areas. The results show that lower ambient pressure leads to a farther nappe trajectory and the trajectory distance increases roughly by 1.5% when the ambient pressure drops by 10 kPa. Thus, particular attention should be paid to this ambient pressure factor when a relative short plunge pool must be adopted in valley areas to avoid safety risks of plunge pool and bank slope owing to the error in estimation of the nappe trajectories.