珠江三角洲平面二维盐水入侵数值模型研究

A 2-D numerical model for salt water intrusion in the Pearl river delta

珠江三角洲咸水入侵是一个近年来备受关注的课题。珠江三角洲河道纵横交错,口门数目众多,水动力因素错综复杂。数学模型以其经济、省时的优势成为珠江三角洲咸水入侵预报的主要研究手段。该模型网格采用三角形与四边形结合的混合网格形式,计算区域包括珠江三角洲网河区、八大口门以及外海部分海区。采用同步水文资料对珠江三角洲的盐度场进行了模拟,验证结果显示模型计算的潮位、流速、以及盐度等与实测资料吻合较好,模型成功复演了珠江三角洲的潮流和盐度的变化过程。在模型验证良好的基础上,通过计算1999年和2005年不同地形条件的咸潮上溯情况,可知由于河道地形下切严重已导致2005年咸潮上溯程度明显加剧,给更多居民日常用水带来困扰。

The problem of saltwater intrusion in the Pearl river delta is very serious especially in recent 20 years. The Pearl River network is complicated with hundreds of channels connected and 8 outlets in the downstream, which makes the hydraulics in the delta much more difficult to analyze. Numerical model is considered as the main method to study the saltwater intrusion because numerical simulation can reduce cost and time as well. To analyze the process of saltwater intrusion, we set up the model with a combined mesh style （triangular and quadrilateral） , which covers both the Pearl River network and the estuary, and finite volume method is applied to discrete the space. The result showes that the calculation values of tide level, flow velocity and salinity are consistent with the measured data, which proves that this model can be applied in real engineering.