湛江湾三维潮汐潮流数值模拟

Three-dimensional numerical simulation of tidal current in Zhanjiang Bay

基于采用不规则三角网格和有限体积方法的FVCOM模式,建立湛江湾附近海域的三维潮汐潮流数值模型,通过验证,结果与观测数据符合良好,重现了湛江湾的潮位和潮流变化状况。根据模拟结果计算得湛江湾的潮汐有明显不规则半日潮特征,主要分潮波M2、S2、K1、O1主要从外海传入,不构成独立的潮汐系统,其中M2分潮的最大振幅为109 cm;湛江湾海域主要为不规则半日潮流,1日内出现2次涨落潮流,涨、落潮最大流速分别为104 cm.s-1和123 cm.s-1,落潮流流速大于涨潮流流速;湛江湾湾口处海域较开阔,基本为旋转流,而近岸海区基本为往复流,湾内M2分潮流的椭圆长轴占绝对优势。表层潮余流最大流速近30 cm.s-1,湾内余流的总体效应值向湾外,湾口余流较大,对湾内水交换效应有一定积极作用。

Based on an unstructured grid,finite-volume coastal ocean model（FVCOM）,the complete three-dimensional fine-solution equation group of shallow-sea tide is adopted to calculate the tide in Zhanjiang Bay.The equation group consists of tide-control equations and obturating turbulence equations.Using harmonic analysis of the calculated tidal level and current,the distributions of co-tidal lines for M2,S2,K1 and O1 are obtained,with 109 cm,the maximum amplitude of M2,There＇s two flood and ebb tides in 24 hours,and the maximum speed of flood and ebb tidal current can reach 104 cm·s^-1and 123 cm·s^-1respectively.Through the analysis of M2 and K1 tidal current ellipses,we can know that the flow is reciprocating flow in the near shore area,estuaries and channels.The maximum speed of surface residual current is 30 cm·s^-1and the direction of overall effect of the residual current is toward the outside of the bay.