太湖梅梁湾三维水动力学的研究──Ⅰ.模型的建立及结果分析

STUDIES ON A THREE-DIMENSIONAL HYDRO-DYNAMIC MODEL FOR MEILIANG BAY,TAIHU LAKE──Ⅰ.MODEL DESCRIPTION AND RESULT INTERPRETATION

建立了一个太湖梅梁湾三线水动力学模型，模拟了框架湾的水平及垂直流场分布。结果表明：（1）表面流场与风向一致，而底层流场与表面流场的方向完全相反，表现为很明显的补偿流；（2）水平流速基本上自表层向下递减，过渡层的流速比表层和底层小；（3）在风场的作用下可产生垂直环流系统，其中在东南风的作用下产生逆时针的垂直环流（由南向北看），而在西北风的作用下产生顺时针垂直环流；（4）垂直速度自岸边向湖中心递减，其量级远小于水平流速。

In a three-dimensional model of wind-driven crrents in Meiliang Bay of Taihu Lakedeveloped in thes study, the water mass is divided into five layers vertically and the leap-frogmethod is used. The model is used to simulate the horizontal and vertical crrents in Meiliang Bay.The currents are computed from the following equations:Where u,v,w are currents for x,y,z directions, respectively, p is warer pressure, p is water density, gis acceleration of gravity, Ah,Av are horizontal and vertical diffusion coefficients.After a constant southeast erly wind blows for 30 hours, the surface layer flow field accordswith the wind direction, but the near lake bottom flow opposes tha of the surface flow and showscharacteristics of compensation flow. In addition, there exist vertical currents in the lake under thelasting artion of wind. Looking from south toward north, a counterclockwise cireulation is formed inthe vertical profile in response to southeast erly wind and a clockwise cireulation is formed, inassociation wim northwesterly winds. The results also show that the absolute horizontal flow velocitydecreases from the surface to the bottom, whilst the absolute venical now velocity decreases fromthe shore line to the center of the lake.