摘要
潮流的流速分布和湍流切应力的分布密切相关。为了研究潮流湍流切应力的特征和变化规律,本文从潮流运动方程推导出随潮流呈周期性变化的湍流切应力随深度的分布表达式。从江苏近海现场实测流速剖面中计算得到一个潮周期内的湍流切应力的变化过程。通过将实测值与本文理论解的比较发现,计算值能很好地反映出实测值的变化特征,尤其是能正确地反映潮流在加速和减速过程中,湍流切应力偏离线性分布呈现上凹和下凹的现象,以及只有在加减速转换的时候切应力才呈现线性分布的特点。最后,通过分析湍流切应力振幅及相位沿水深的变化情况,认为反映潮流周期、涡粘性和水深之间关系的参数Ri是决定湍流切应力弯曲程度及分布形态的重要参数。对于近海潮流,水深是影响湍流切应力偏离线性程度的主要因素。
Turbulent shear stress is an important dynamic force of flow in a tidal channel, whose distribution affects directly the velocity profile. In this paper, we derived a new theoretical expression of vertical distribution in tidal turbulence shear stress, with which stress development over tidal cycles can be profiled. We applied this model successfully for the turbulent shear stress obtained from a 25-hour velocity profile from field measurement over tidal circles near the Yangkou Harbor off Jiangsu coast, East China Sea in September 2013. Comparison between simulated and the measurement data shows good agreement in vertical distribution. The model can well depict concave during tide acceleration and convex during deceleration. By analyzing the amplitude and phase variation in water column at different depths, we found that the non-dimensional parameter（Ri） reflecting mutual relationship among tidal period, turbulence intensity, and water depth, determines the curvature of turbulence shear stress distribution in a tidal period. For off-coast tides, however, local water depth is the main factor affecting the deviation from linearity of the turbulent shear stress.
出处
《海洋与湖沼》
CAS
CSCD
北大核心
2015年第5期995-1000,共6页
Oceanologia Et Limnologia Sinica
基金
国家自然科学基金青年项目
41306078号
国家自然科学基金面上项目
41076008号
关键词
潮流
湍流切应力
流速剖面
潮流加速
tide
turbulent shear stress
velocity profile
tidal acceleration
