【作者】 邹华志；

【导师】 李华军；

【作者基本信息】 中国海洋大学 ， 港口、海岸及近海工程， 2010， 博士

【摘要】 珠江河口水系以“河网如织,八口入海”为特征,其河网、河口和近海水域构成了一个相互贯通的多河道、多河口的水流系统,上游径流、外海潮汐等因素在这个系统内相互作用、相互影响,形成了极为复杂的水动力环境。本文研究目的是要实现对河网-河口-近海这一连续水体的整体数值模拟,以期更真实的反映河网与河口、河口与近海及河口各口门间的相互影响和耦合作用,并在此基础上对珠江河口咸潮上溯问题进行相应的数值模拟研究。为此,本文首先建立了适用于复杂河网的一维水流、盐度数值模式,并在数值模式的求解过程中引入了节点水位法,有效提高了计算效率；其次,引入了基于无结构三角形网格、有限体积法和三维海洋原始方程组的海洋河口模式FVCOM,充分利用其网格布置灵活的特点,对计算网格进行了优化布置,实现了珠江河口大范围高分辨率的三维数值模拟；基于守恒定律,推导了两种适用于一、三维模式联解的算法,与以往算法不同,河网模式的水动力部分直接与FVCOM的二维外模联解,有效提高了计算效率；最后,基于联解算法成功实现上述两模式的整体联解。利用丰富的实测、遥感资料分别对模式进行了率定和验证,计算结果和实测、遥感数据吻合较好,模式能较好的模拟相应的水动力和盐、淡水混合与扩散过程,具有较好的精度,证明本文所发展的模式是可以应用于珠江河口咸潮上溯问题研究的。将模式应用于珠江河口,利用整体联解模式,创造性的实现了珠江河口水系河网-河口-近海的整体数值模拟,且计算网格具有较高的分辨率,能够准确拟合曲折岸线和多变的水下地形,使得模式能够充分体现河网与河口,河口与近海及河口各口门间的相互影响和耦合作用,计算精度得到了一定程度的提高；利用计算结果,对珠江河口水系咸潮上溯过程和机理进行了详细、深入的分析,提出了珠江河口盐、淡水输移“盐水东进,淡水西飘,深入浅出”的基本动力机制；开展了基于机理研究的(Process oriented)数值模拟试验,依据计算结果分析了径流、潮汐、地形、风、人类活动等各影响因素对珠江河口咸潮上溯的影响。更多还原

【Abstract】 River, estuary and shallow sea composes a consecutive and integral water system, in which multiple forces (river discharge, tide, wave, wind, etc.) and different natures (temperature, density, salinity, etc.)coexist and interact with each other. Its dynamic is rather comprehensive. Further more, the Pearl River Estuary (PRE) is a multiple river/estuarine system with complex coastal geometry and abruptly varying bathymetry. These pose a great challenge for researchers to develop a computationally efficient and accurate numerical modeling system for the synchronous simulation of this integral and consecutive water system of PRE, especially its application on seawater intrusion.In order to study the physical mechanism and spatial/temporal structure of the seawater intrusion at PRE, A river network-estuary coupled numrical modeling system has been developed in this paper. For gaining computational efficiency, the river network is treated as one-dimensional and a one-dimensioanl river network model has been developed firstly. For keeping the vertically stratified nature of the estuarine hydrodynamics, and computational efficiency as well, a three-dimensional unstructured-grid Finite-Volume Coastal Ocean Model (FVCOM) is introduced and utilized.These two individual models are coupled through the principle of the conservation of mass, and that of momentum, at their interfaces. By doing so, a good balance between accuracy of large-scale simulation and computational efficiency has been properly achieved. The newly developed modeling system is then tested for the Pearl River and its estuary. Good agreements between calculated results and field data indicate that employing this coupled modeling system is highly efficient and capable of capturing dynamic processes of the entire water system correctly.Then, the developed numerical modeling system has been successfully applied to the simulation of seawater intrusion in PRE.According to calculated results, the basic mechanism of seawater intrusion in PRE has been indicated that the diluted water drifts westward following the ebb tidal current and seawater mainly intrudes upward into estuarine bays from east-south. In addtion, several process-oriented model runs has been conducted to study the effect of river discharge, bathymetry and wind on seawater intrusion.更多还原