河口海岸潮流速分布模式研究

Study on the tidal velocity profile in the estuarine and coastal areas

在沿岸水域尤其是在浅海陆架和近岸区,潮流在水流运动中起着主导的作用,在潮流运动中,近底流速剖面偏离传统的对数分布。根据前人的研究,笔者曾从理论上得到了近底流速分布的对数线性模式。但该模式对近底层的数据要求较高,一般近底1m之内需要四层测量数据,而这些数据在实际应用时很难得到。因此,本文根据潮流运动的表面边界条件将该模式进行扩展研究,使其能适用于传统的六点法测量数据。该扩展模式为对数抛物模式,适用于全水深,是潮流速分布模式。通过长江口和江苏岸外西洋海域两个实例计算分析,并与传统的对数分布模式比较,结果表明该潮流速分布模式在各层数据上都与实测数据具有良好的相关性且物理量z0与u*之间具有更好的一致性和相关性,可应用于河口海岸流速分析研究。

Tide current plays a dominant effect on flow near shore especially in continental shelf and along coast. In the process of tidal motion, the near bottom velocity profile deviates from traditional logarithmic distribution. According to previous studies, the log-linear velocity distribution model was deduced theoretically. The model has high demand on near bottom velocities, needing four layers velocity data within 1 m on average. Considering the difficulty of obtaining such kinds of data in practice, the log-linear model is extended based on the surface boundary condition of tidal current in order to be applied to traditional six points method measurement data. The extended model is log-parabola model and can be applied to the whole flow depth. Through the two practical examples, the Yangtze River Estuary and Xiyang offshore zone in Jiangsu coast, it could be concluded that the extended log-linear model revealed the better correlation and consistency with measured data in each layer than the traditional logarithmic model and can be applied to the analysis and study of estuarine and coastal velocity data.