中文摘要：

在恒定时间连续点源条件下,从移流扩散方程的完全三维解析解出发,给出了顺直铅垂岸大宽度深水水库污染混合区的解析计算方法和等浓度曲面方程,分析了污染混合区的断面和平面形状的变化规律;以污染混合区下游长度Ld为特征长度,定义了佩克莱特数Pe,给出了污染混合区无量纲上、下游长度、最大宽度与最大深度及相应纵坐标和面积的计算公式及其诺莫图。表明污染混合区的无量纲尺度主要取决于佩克莱特数,其次无量纲最大宽度和面积还与λy、无量纲最大深度还与λy和λz有关。给出了非保守物质污染混合区的修正计算方法以及保守与非保守物质的计算分区图;完整系统地提出了三维移流扩散方程定量化的简化条件。该解析方法和计算公式可为天然水库污染混合区的估算提供有力的工具。

英文摘要：

This paper presents an analytical method for the 3D pollutant distribution in a mixing zone of a plumb bank reservoir,which is based on the analytical solution of advection-diffusion equation under the condition of a steady continuous point source of conservative substance. The concentration contours obtained in this work shows the shapes of mixing zone boundaries on horizontal plane and vertical cross-sections. By selecting the downstream length of mixing zone as the characteristic scale of Peclet number Pe,analytical formulas and Nomograph are obtained for the calculation of dimensionless lengths,maximum width and depth and their locations,and the polluted areas upstream and downstream. The results show that the dimensionless scales of mixing zone depend on Pe,and the maximum width and area are interrelated to the maximum depths λy and λz. This paper extends the method to the case of non-conservative substance transport and obtains a modified method for the mixing zone and a zonal diagram for calculating the two types of substances. Thus we put forward a complete and systematical method to simplify the conditions of the advection-diffusion equation. The analytical method is a reliable tool for evaluation of pollutant mixing zone in natural reservoirs.