A NUMERICAL MODEL FOR TIDAL CURRENTS IN THE CHANGJIANG RIVER ESTUARY

A generalized finite difference scheme is presented for the solution of two-dimensioned tidal current equations (averaged over the depth of water). This method has been used to simulate the tidal currents in the Changjiang River estuary, with computed results being in good agreement with the field observations. The two-dimensional domain consists of triangular elements with acute angles. First- and second-order partial derivatives are defined at nodal points. In addition, the basic tidal current equations contain an extra term to account for horizontal eddy viscosity. The method has the great advantage of allowing a wide flexibility in configuration simulation, thereby exhibiting the capability to arbitrarily subdivide the region of interest as well as to provide a more accurate boundary shape, and what is more, it offers savings in computing costs.     

连云港潮流的数值模拟

连云港位于江苏省东北角,海洲湾以南,是我国五大重点港口之一。为了适应四个现代化建设的需要,连云港的整治和扩建具有重要的经济意义。在连云港物理模型进行试验的同时,我们开展了数学模型的研究。由于物理模型受到场所、设备、时间及劳力的限制,因此,寻找周期短花钱少的数学模型就势在必行了。因为数学模型在复演或预演水流现象时修改模型方便,能迅速提供多种方案供人们选择,因而它可与物理模型相辅相成,取长补短。     

长江口潮流的一种数值模式

为了解二维潮流方程(在水深上求平均),本文给出了一种一般化了的有限差分格式。应用这个方法模拟了长江口的潮流,计算结果与现场观测资料相当一致。 平面区域是由锐角三角形元素所组成。在节点上,一阶和二阶偏导数已被定义。在潮流基本方程中,水平涡动粘滞项也已考虑。 这个方法有一个很大的优点,能灵活地模拟图形,即边界更精确和在感兴趣的区域能被任意分割。而且,这个方法是经济的。