长江口深水航道三维异重流分布特性和湍流混合机理研究

项目名称： 长江口深水航道三维异重流分布特性和湍流混合机理研究

项目编号： No.51279134

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 水利工程

项目作者： 黄文锐

作者单位： 同济大学

项目金额： 80万元

中文摘要： 异重流是影响长江口深水航道回淤的重要因素之一。本项目将研究深水航道异重流的分布特性和湍流混合机理。通过室内模型实验，观测湍流混合现象和异重流分布特性，分析底部回流强度与密度差的关系，研究异重流的形成机理，以及加深航道对底部回流的影响。进行长期定点的异重流动力因素现场测量（流速、盐度、温度），过滤和潮汐和风因素的影响，分析异重流与盐度梯度及流量的关系。利用ADCP进行航道二维断面流场测量，分析深水航道不同区域的异重流分布特性。建立深水航道三维水动力异重流模型，利用长期现场实测资料对模型参数进行率定；针对湍流模型在有密度差的航道中存在的局限性，对二阶湍流模型进行改进研究；通过与现场实测资料比较，评估二阶湍流模型的误差范围，提出改进湍流模型的方法，使其能可靠地计算异重流的混合强度；揭示异重流在深水航道中的时空变化过程，探讨减轻异重流对航道回淤影响的措施。

中文关键词： 异重流；湍流；深水航道；数值模型；实验观测

英文摘要： Density-induced current is one of the key factors for the sediment deposition in the deep-water navigation channel in Yangtze estuary. In this study, characteristics of 3D density-induced currents and turbulence mixing in the deep navigation channel will be investigated. Laboratory experiments will be conducted to observe the mixing phenomena between fresh and salt waters, analyze the relationship between density gradient and the resulting currents, and study the mechanics of the density-induced current and its response to the increase of channel depth. Long-term field observations will be conducted to collect data of currents, salinity, and temperature. Relationship between density gradients and density-induced currents will be analyzed by filtering signals of winds and tides. Based on the analysis of 2D ADCP measurements of currents in selected cross sections, spatial distributions of density-induced currents will be characterized. A 3D hydrodynamic model capable of modeling density-induced currents will be setup for the navigation channel. Considering the limits of most of turbulence model under the density-gradient effects, efforts will be conducted to enhance 2nd-order turbulence modules. Based on the comparison with field observations, error ranges resulting from turbulence models will be evaluated. New me

英文关键词： gravity flow；turbulence；navigation channel；numerical modeling；experimental study