甬江河口洪季三维水沙动力和泥沙捕集机制研究  

Study on three-dimensional water-sediment dynamics and mechanisms of sediment trapping in wet season of the Yongjiang estuary

作　　者：祝仁杰 陶建峰[1] ZHU Ren-jie;TAO Jian-feng(College of Harbour,Coastal and Offshore Engineering,Hohai University,Nanjing 210098,China)

机构地区：[1]河海大学港口海岸与近海工程学院,江苏南京210098

出　　处：《泥沙研究》2023年第1期49-56,64,共9页Journal of Sediment Research

基　　金：国家自然科学基金项目(52071129)。

摘　　要：结合2015年洪季测验资料和三维斜压水流泥沙数学模型,研究了甬江河口的纵、横向余流结构及最大浑浊带特征,并根据动量平衡分析方法探讨了余流动力及泥沙捕集机制。结果表明:大潮期纵向余流受纵向对流项和正压梯度项主导呈下泄趋势,小潮期口门底部存在较大的向陆斜压作用,形成河口环流;盐度较低的上游弯道横向余流受纵向对流项和正压梯度项主导,表层指向凹岸、底层指向凸岸,而下游弯道横向环流结构受斜压梯度项影响大,过渡直道段横向余流呈表层收敛、底层发散的双环流结构;大潮时最大浑浊带位于清水浦,小潮则下移至镇海;弯道处泥沙横向捕集于凸岸侧,而过渡段仍聚集于深槽内。Combined with measured data in June 2015 and three-dimensional baroclinic flow and sediment numerical model, the structure of longitudinal and lateral residual current and characteristics of the estuarine turbidity maximum in the Yongjiang estuary are studied, and mechanisms of residual current and sediment trapping are discussed according to the momentum balance analysis. The results show that at spring tide, longitudinal residual current is dominated by longitudinal advection and barotropic pressure gradient terms, showing an outflow trend. At neap tide, a significant landward baroclinic effect emerges around the river mouth, forming estuarine circulation. Lateral residual current at upstream bends is dominated by longitudinal advection and barotropic pressure gradient terms, with flow toward the concave bank at surface and toward the convex bank near bottom, while at downstream bends is greatly affected by the baroclinic gradient. In transition straight reaches, the lateral residual current presents a double-cell circulation with surface convergence and bottom divergence. During spring tide, the estuarine turbidity maximum is located near Qingshuipu, and moves down to Zhenhai at neap tide. Sediment at bends is laterally trapped on the convex bank, while in transition reaches is still concentrated in the deep groove.

关 键 词：余流 最大浑浊带 横向动力 动量平衡分析 泥沙捕集 甬江河口 

分 类 号：TV148.1[水利工程—水力学及河流动力学]