象山港余流特征数值研究

Numerical simulation study on the residual currents in the Xiangshan Bay

基于Delft3D-Flow模块建立了象山港海域的三维斜压潮流数值模型,结合实测水文资料,研究了象山港的潮(余)流特征,对欧拉余流场的时空分布进行了定量的比较和分析,并与潮流测站计算分析得到的欧拉余流分布对比,很好的模拟了象山港的余流特征。结果表明:由湾外至湾顶,余流呈减小的趋势,湾外余流最大为33 cm/s,湾顶最小,余流平均仅5 cm/s。垂向上,表层余流大于底层余流,表层余流指向湾外,而底层余流则指向湾内。对比斜压、正压两种模式下的欧拉余流分布,可以看出湾顶附近主要受径流控制,两种模式得到的结果基本一致,口门至西沪港区域受径流和潮流的共同影响,斜压模式更准确地模拟出了水体层化和垂向余环流结构。

A three-dimensional baroclinic numerical model of tidal currents in the Xiangshan Bay is built based on Delft3D-Flow. The numerical model, combined with the observational data, is used to investigate the characteristics of the tidal currents in the Xiangshan Bay. Furthermore, the spatial and temporal distribution characteristics of the Eulerian residual currents are quantitative analyzed. The results show that the tide induced residual current is reduced from the entrance to the top, and the scale is 5～33 cm/s. The surface layer is larger than the bottom in the vertical, and the surface direction of residual currents points to the outside, while the bottom turns to the top. Compared the distribution of the Eulerian residual current with barotropic version and baroclinic version, it＇s known that the top area is controlled by the runoff, and there is little difference between two patterns. Near the entrance of the XiangShan Bay, the water is influenced by the tidal current and runoff, and the baroclinic version is more preferable to simulate the stratification and residual circular currents in the vertical.