河口垂向拉格朗日余环流研究

应用弱非线性理论导出了狭窄型河口内拉格朗日余流的控制方程和溶解质长期输运方程,并应用流速分解法和B—样条配置技术建立了潮汐及拉格朗日余流的数值模型,应用欧拉—拉格朗日方法和B—样条配置技术建立了长期物质输运方程的数值模型,对狭窄型河口内潮致—斜压拉格朗日余环流进行了研究。结果表明,河口垂向拉格朗日余环流,不同于欧拉余环流,呈现一种较复杂的流型,在盐水入侵界的上游可能存在一涡旋。作者提出,将河口按余环流生成机制和水动力特征分为斜压,潮控及河流三个区。

ON THE VERTICAL LAGRANGIAN RESIDUAL CIRCULATION IN NARROW ESTUARIES

Eased on the weakly nonlinear theory, the governing equation of mass -transport velocity and the long - term transport equation are derived for narrow estuarine systems. By means of the Current Separating Method and the B -spline collocation method, the numerical models of tide and Lagrangian residual current are established. The numerical scheme of long -term transport equation is based on the Eu-lerian - Lagrangian method and the B - spline collocation method. The tide - induced baroclinic vertical Lagrangian residual circulation in a narrow estuary is studied numerically. The result reveals that the pattern of Lagrangian residual circulation is more complex than that of Eulerian residual circulation. In the upper stream of salt water intrusion,there may exist a Lagrangian residual vortex. According to the characterastic and generation mechenism of the residual circulation , we suggest dividing an estuary into three parts: a barociinic zone, a tide - dominated zone and a(?)ver zone.