中文摘要：

为分析突发状况下典型强潮河口污染物的扩散输移机理，提出恰当的应对措施以尽量减小污染物对水质的影响，基于正交曲线坐标系中不可压缩、Boussinnesq本构关系假定下的Navier—Stokes方程，对钱塘江河口发生突发性污染事件时污染物的扩散输移进行了数值模拟，并通过改变上游边界条件获得了不同径流量下的污染物扩散状况．计算表明：一旦钱塘江河口受污后污染物既在径流作用下向下游输移扩散，也在涨潮流控制下向上迁移影响上游水质，受污各点的污染物浓度大小变化在每个潮周期内与相应的水位涨落变化相反．加大钱塘江河口的上游流量能够加快污染物的迁移扩散，有利于减小污染物对上下游水质的影响，从而达到尽快消除污染实现水质安全的目的．

英文摘要：

In order to study the diffusion and transport characteristics of abrupt pollutants in a macrotidal river and to propose appropriate measures to respond to minimize the impact of pollutants on water quality, Navier-Stokes equations for an incompressible fluid in orthogonal curvilinear co-ordinates under the Boussinnesq assumption were used to numerically simulate the diffusion and transport of abrupt pollutants in Qiantang estuary, and the pollutant dispersion under different runoff were obtained by changing the upper reaches of the boundary is conditions. Results indicate that once Qiantang estuary is contaminated, the pollutants diffuse to downstream under the influence in the run-off, and by the effect of flood current the pollutants also impact the upstream water quality. The pollutant concentration at each contaminated point changes in the opposite way to the corresponding water level fluctuation in each tidal cycle. Increasing the upstream flow can accelerate the pollutants diffusion, it is conducive to reduce the pollutants＇ impact on water quality at upstream and downstream, and it also favours eliminating the pollutants quickly and achieving water quality safety.