珠江虎门河口洪季潮流近底边界层水流结构研究  

Measurements and analysis on flow structures of tidal boundary layer at the bottom of Pearl river estuary

作　　者：尹小玲[1,2] 张红武[2] 刘欢[3] 

机构地区：[1]华南理工大学水利水电工程系,广州510640 [2]清华大学水沙科学与水利水电工程国家重点实验室,北京100084 [3]中山大学近岸海洋研究中心,广州510275

出　　处：《水力发电学报》2010年第1期158-163,共6页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金项目(10972080);国家自然科学基金项目(50339020)

摘　　要：研究河口近底边界层水动力结构对进一步研究河口地区水流能量耗散和物质输运具有重要意义,2006年7月26-28日在珠江虎门口采用ADV、ADP及OBS和CDT组合置底支架观测系统对近底边界层水流、泥沙和温盐度进行了水下定点观测,本文通过分析流速观测数据,对该潮汐河口近底边界层的水流结构、阻力特性和紊动尺度进行研究,结果表明除憩流附近外,近底边界层内时均流速分布均可采用对数剖面,摩阻流速值与时均流速基本成正比,平均摩阻流速为0.014m/s,粗糙长度为0.09mm,切应力梯度为0.426N/m^2·m; 脉动流速统计分析结果符合典型潮汐河口底边界层的紊动特点,距床面0.15m处,落急时刻宏尺度紊动的时间尺度和长度尺度分别为3s和0.06m; 垂向脉动分速以及瞬时雷诺应力自相关分析表明转流附近时段的湍流主要以低频大尺度紊动为主。测量分析结果可为下一步研究近底边界层泥沙运动提供依据,并为数值模拟计算提供水动力分析条件和特征参数。The current of tidal boundary layer at the river bottom was measured in situ by ADP and ADV on July 26-28th, 2006 to study flow structures, resistance and turbulent scales. Results show that the current velocity generally follows a logarithmic profile except for slack time, that the frictional velocity with its mean value of 0. 014m/s is proportional to the mean current velocity. A hydraulic roughness of 0.09ram and a shear stress gradient of 0. 426N/m^2· m were measured. The statistics of velocity fluctuations is close to that of typical tidal estuaries. Macro turbulence scales at maximum ebb tide are 0.06m and 3 sec. Autocorrelation of vertical velocity fluctuations and Reynolds stress indicates the dominance of a large-scale low-frequency scales around slack periods. This work provides useful data for further study of numerical simulation or sediment movement.

关 键 词：水动力学 珠江河口 潮流底边界层(TBBL) 水流结构 现场观测 

分 类 号：TV131.2[水利工程—水力学及河流动力学]