杭州西湖换水的掺混特性

本文以水温垂线分布和水体物质浓度平面分布的现场实测资料为基础,考虑了风对浅水湖泊的显著效应,通过密度福氏数的分析,阐明了西湖中的小南湖换水时水体运动特性及其所属类型.在此基础上,导得物质浓度变化的计算式,并用实际资料予以验证,从而对改善湖水水质的经济合理换水方式进行了原则探讨.

Behavoir of Mixing in Flushing Process of the West Lake

Based on the field measurement of concentration at 29 points in Xiaonanhu of the West Lake and the analysis of its order of the Densimetric Froude Number, this paper shows that the behavoir of flow in the lake belongs to the well-mixed type, which coincides with the result of hydraulical investigation of other similar lakes. The equation of continuity of substance in water is thus derived and well verified with field data, the discrepancy being less than 10%. The relationship between the quantity of fresh water diversed in and the diluted concentration in the lake can be evaluated arid economical and reasonable quantity and duration of diversion can be dertermined. Some suggestions regarding the improvement of water quality of the lake are made.