【作者】 陈娟；

【导师】 张万顺； 叶闽；

【作者基本信息】 武汉大学 ， 环境科学， 2005， 硕士

【摘要】 根据研究水资源保护工作的需要,提出一个平面二维水流—水质有限体积法及黎曼近似解模型。有限体积法(FVM)的方程是对控制体写出的积分形式的物理守恒律,把二维问题转化为一系列局部的一维问题进行求解。该法将计算域划分成若干规则或不规则形状的控制体,对每个控制分别进行水量和动量平衡计算,得出各控制体边界沿法向输入或输出的流量和动量通量,然后便可计算出时段末各控制体的平均水深和流速。 本文中模型以高精度的向量分裂格式(FVS)通过求解局部黎曼问题来估算各网格边界上的法向通量,具备有限单元法及有限差分法两者的优点,不仅提高了数值模拟的精度,而且能模拟包括恒定、非恒定或急流、缓流等水流.水质状态。 利用长江和汉江武汉段相关水域的实测资料对模型进行率定和验证,验证结果表明:二维水流—水质耦合模型对区域概化合理,模拟结果基本反映了河道的水力特性和水质特征,可用于模拟区域内污染物迁移降解过程和污染带影响范围的预测。 在水资源管理中的点源入河排污论证应用中,分析了正常排放和突发事件排放情况下对水功能区的影响:对概化的污染源模拟出在设计条件下的污染带分布图,并计算出污染带长、宽随排污量变化曲线,并对所在长江江段水质可达性进行了研究。 在面源排污论证应用中,定量估算分析了赫山地区城市面源降雨径流过程和污染负荷。在此基础上,用二维水流—水质耦合模型分析了正常排放、事故性排放和面源治理后排放情况下对水功能区的影响,计算出污染带长、宽随河道水期变化曲线,并对所在汉江江段水质可达性进行了研究。为城市降雨径流的排放论证做了一个尝试。 数值模型应用表明,有限控制体积法(FVM)配合向量分裂格式(FVS)是一种具有高解析度的数值方法。二维水流水质FVM模型是合理的、可靠的和有效的,可在实际工程水环境工作中推广运用。更多还原

【Abstract】 A depth-averaged two-dimensional river water quality model is developed for water resources protection. The basic equation of the finite volume method, FVM, is obtained, using the divergence theorem. Meshes are used to represent the computational domination. In the framework, a finite volume method on a structured or an unstructured grid has been developed. The model transfers 2-D problem to a series of local 1-D problems. Firstly, the mass and momentum fluxes through each mesh are calculated according to the balance theory. Then the water elevation and depth-averaged velocity of each mesh are obtained.One of the attractive features of this model is to treat the calculation of the mass and momentum flux across with the flux vector splitting scheme (FVS). It uses the merits of the finite difference method and the finite element method. The model employs FVS-type approximate Riemann solver to estimate the numerical flux across the interface among cells with high accuracy.The model has been examined and verified by on-the-spot survey datas of WuHan section of Yangtze river and HanJiang river. The results show the water-quality characteristics of the studied watercourse. It is proved that the model is validating reasonable and applicable. In the environmental managing works, the model can be used to analyse transfer and degradation of contamination and predict the relationship between the area of the belts and the discharged pollutions.In the example of the argumentation of the point source pollution of WuHan breach of Yangtze river, the paper construes the influences which the discharged industrial waste water does to the studied water area on condition of normal and accidental discharged. The model computes the main pollutant mixed belts in generalized pollution point, and the relationship between the area of the belts and the discharged pollutants. The water quality of the river and suitable pollution control measure are given.Sample applications of this model to the non-point pollution flow of WuHan breach of HanJiang river, as to rough estimate storm runoff and pollution loading in HeShan Area of WuHan city. Based on the hereinbefore works, the paper analyse the main pollutant mixed belts and relationship between the area of the belts and the discharge pollutionwhen it is discharged in the manner of normally, or accidentally, or treated . On the reasoning of area source of storm runoff discharged in city , the paper commence a good attempt.Results calculated with the design method suggested that the model can meet the environmental engineering requirements. Additionally, the model is improved to simulate the flow affected remarkably by tide and river bend. The model can be practically generalized to managing works of water resources.更多还原