河口冲淡水运动理论模式及数值应用(续)——(Ⅱ)数值应用

2 计算结果和讨论2.1区域特征和参数选取 具体数值模拟在图2区域上进行。区域水平尺寸为60×80km;河口口门宽5km、深5m;计算网格间距△x=△y=2.5km。海底底形考虑图3类型。其它参数取值在后面的流函数分布图中予以说明。

A THEORETICAL MODEL OF ESTUARINE DILUTED WATER AND ITS NUMERICAL APPLICATIONS

Based on the nonlinear shallow water equations, this paper develops a model in which the positive and negative mass fluxes located at the mouth of the estuary are the driven mechanisms of water body motions. After the governing equations have been nondimensionlized, the perturbation procedure is engaged. The zero -order e-quations describe the balance of the effects of the Coriolis force, bottom frictioon and topography; in addition to the zero -order equations, the first order equations have inner' source -sink' terms. To the upper diluted water, the inner'source -sink' term is the zero -order interfacial friction of the upper water; to the lower shelf water, the inner' source -sink' term is the zero -order advection effect of the lower water. The computational results show that for linear or logarithmic bottom topography, the flow of the upper diluted water bifurcates into two branches: one deflects toward the right bank (facing downstream in the northern hemisphere), the other veers to the left. A brief comparison is made between the results of this model and the observations for the Huanghe River (the Yellow River) (in China), the Tsugaru Strait (in Japan) and the Columia River (in USA) estuaries.