风场对岗南水库水体滞留时间及污染物扩散的影响研究

Influence of Wind Field on Water Residence Time and Pollutant Diffusion in Gangnan Reservoir

摘要:

为探究风场对岗南水库滞留时间的影响,建立了岗南水库水动力和水体交换模型,设置5种不同风向工况模拟了水体滞留时间,建立了各分区的连通性矩阵,结果表明:风场作用使整个库区水体流速增大,在东风、西风和北风条件下,库区内形成了2个大小、方向不同的环流,且1个环流主要在Ⅱ、Ⅲ、Ⅳ和Ⅶ区,1个环流主要在Ⅳ、Ⅹ库区;南风条件下,库区内主要在Ⅱ、Ⅲ、Ⅳ区形成了4个大小、方向不同的环流;有风条件下库区的整体滞留时间略高于无风条件,但两者相差不大。风场对主库区和库湾区滞留时间影响不同,风场作用下主库区的滞留时间略有增加,但库湾区滞留时间明显缩短;风场对主库区Ⅰ—Ⅳ污染物扩散的影响不大,对库湾区污染物扩散影响较大,加速了库湾区污染物扩散。在有风的条件下引水不仅可以增大流速,还可以增加各库区(尤其是库湾区)水体之间的连通性,提高水体交换能力,有助于改善水质。

Abstract:

In order to explore the influence of wind field on the residence time of Gangnan Reservoir, a hydrodynamic and water exchange model of Gangnan Reservoir was established. Set five working conditions of different wind direction , established connectivity matrices for each partition. The results show that the wind field increases the water flow velocity in the whole reservoir area. Under the condition of east, west and north wind, two circulations with different sizes and directions are formed in the reservoir area, and one circulation is mainly in areas II,III,IV and VII, and the other one circulation is mainly in areas IV and X. Under the condition of south wind, four circulations with different sizes and directions are formed in areas II,III and IV. The overall residence time of the reservoir area under windy conditions is larger than that under windless conditions, but the overall residence time is not much different. Furthermore, The influence of wind field on the residence time of main reservoir area and bay area is different. The residence time of main reservoir area increases slightly under the action of wind field, but the residence time of bay area is significantly shortened. The wind field has little effect on the diffusion of Ⅰ to Ⅳ pollutants in the main reservoir area. Wind field has great influence on the diffusion of pollutants in the bay area, which accelerates the diffusion of pollutants in the bay area. The results show that the water diversion under the condition of wind can not only increase the flow velocity, but also increase the connectivity between the water bodies in the reservoir area, especially in the bay area, improve the water exchange capacity and help to improve the water quality.