摘要
河冰是陆地冰冻圈的重要组成要素,在生消演变过程中影响水流运动规律,受冰凌影响河流流态可分为明流、完全冰封和部分冰封。为探究冰盖下水流的紊动特性,采用声学多普勒三维测速仪测量3种流态的恒定均匀流场,对比分析纵向时均流速、雷诺应力和紊动强度的分布规律。结果表明:完全冰封流纵向时均流速垂向上呈不对称“■”型分布,雷诺应力在垂向上线性分布,紊动强度在基于双层假定划分的冰盖层和床面层均符合指数分布律;部分冰封流纵向时均流速垂向分布兼具明流和完全冰封流的特性,存在横向动量交换,导致冰盖区、明流区和过渡区的雷诺应力和紊动强度在水深方向上也存在明显的差异。试验结果可为冰凌灾害防治和供水安全保障提供理论指导。
River ice,as a vital component of the terrestrial cryosphere,alters the structure of under-ice flows during its evolution.The hydraulic regimes of ice-affected streams may be classified as fully-open,completely-covered,and partially-covered.Using experimental measurements from an acoustic Doppler anemometer,the turbulence characteristics of steady uniform flow under three different hydraulic regimes were studied in terms of streamwise velocity,Reynolds stress,and turbulence intensity.The results showed that for the completely-covered case,the streamwise velocity profile exhibits an asymmetric ■-shape with the maximum value closer to the smooth boundary,the Reynolds stress profile is linearly distributed in the depth direction,and the turbulence intensity profile for two flow layers based on the two-layer hypothesis may be described by an index relationship.The flow structure in partially-covered channels shows a combination of hydraulic characteristics from fully-open and completely-covered flows.Owing to the effect of lateral momentum transfer,the vertical profiles of the Reynolds stress and the turbulence intensity in the under-ice,open-water,and transition subsections differ from each other.The experimental results can provide theoretical guidance for ice-related disaster prevention and water supply security.
作者
陈刚
董增川
王海军
顾世祥
杨红宣
CHEN Gang;DONG Zengchuan;WANG Haijun;GU Shixiang;YANG Hongxuan(State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering,Hohai University,Nanjing 210098,China;Yunnan Survey and Design Institute of Water Conservancy and Hydropower,Kunming 650021,China;College of Electric Power Engineering,Kunming University of Science and Technology,Kunming 650500,China)
出处
《水科学进展》
EI
CAS
CSCD
北大核心
2023年第2期299-309,共11页
Advances in Water Science
基金
国家重点研发计划资助项目(2021YFC3000205)
云南省技术创新人才培养对象资助项目(202005AD160017)。
关键词
冰盖
紊动特性
流速分布
雷诺应力
紊动强度
ice cover
turbulence characteristics
streamwise velocity
Reynolds stress
turbulence intensity
