中文摘要：

为探讨长江口南港的水动力结构及悬沙侧向输运特征,本文从解析解的角度构建了潮汐河口水沙输运数学模型,并将其应用到长江口南港某横断面上。南港水动力主控于半日潮流,余流主要由陆相径流及本地非线性对流项驱动,悬沙分布上北侧副槽远大于南侧主槽,水沙分布的计算结果与实测结果在结构上基本一致。通过输沙函数进一步分析表明,潮流输沙和余流输沙是南港侧向输沙函数的两个主要部分。南港中强劲径流削弱了涨潮流,增强了落潮流,使得向河槽南侧的涨潮流输沙小于向河槽北侧的落潮流输沙,潮流输沙指向河槽北侧。径流驱动的南港侧向余流在涨潮流方向上为一逆时针环流结构,余流输沙指向河槽北侧。扩散输沙指向南侧主槽,因其总是指向悬沙浓度梯度的负方向。在各输沙因子的综合作用下,南港中大量悬沙捕集于河槽北侧,使得河槽北部底层潮平均含沙量值达到最大值。

英文摘要：

An analytical model was developed to analysis the hydrodynamics and sediment transport in the South Chan- nel of Yangtze Estuary, China. The tidal dynamics in the South Channel is controlled by semi-diurnal tide. The domi- nated driven factors of residual flow are river discharge and nonlinear advection terms due to tidal flow. The suspended sediment concentration over the northern channel is much higher than that over the southern channel. The essential features of the observed flow field and sediment distribution are reproduced by the model results. Closer inspection of the sediment entrapment with sediment transport function indicates that, the residual transport and tidal transport dominates, and both of them point northward （to the north deep channel）. The diffusive transport points southward, since it always transports sediment from high concentration area to low concentration area.