三峡水库香溪河库湾水温分布特性研究

CHARACTERISTICS OF WATER TEMPERATURE DISTRIBUTION IN XIANGXI BAY OF THE THREE GORGES RESERVOIR

建立三维水温数学模型,对2007年三峡水库香溪河库湾及部分库首江段的水温分布特性进行了数值研究。根据计算区域的特点,模型采用贴体网格系统,并充分考虑水体与外界的热交换、入流、出流等因素,利用实测资料率定相关参数后进行模拟,结果表明:(1)香溪河库湾属于季节性水温分层型水体,分层期会有温跃层的出现;但在水平方向上水温差异较小,全年水温在11.1～29.14℃变化。(2)库区干流由于水体紊动作用强,模拟时段2007年全年没有发生水温分层现象。(3)库湾在水温分层期间,表层的水温普遍高于干流,底层局部水温则低于干流,香溪河口存在水平及立面环流与潜流现象,呈现极为复杂的三维流动特性。研究结果可为三峡库区生态环境安全管理提供科学依据。

In this study,a three-dimensional model of water temperature has been developed,and the characteristics of water temperature distribution in Xiangxi Tributary Bay and part of mainstream of Three Gorges Reservoir in the year of 2007 were studied using numerical simulation method.The body-fitted grid system was applied to the computational domain,the heat exchange between the water body and the outside,the inflow,and the outflow were took into account fully,the measured data were used to calibrate the water temperature model.Simulation was undertaken for one year and the results showed that the Xiangxi Bay was the water body of seasonal temperature stratification,and the thermocline could be observed during stratification.However,the temperature difference was smaller in horizontal plane.The annual water temperature changed from 11.1℃ to 29.14℃.The phenomenon of water temperature stratification in the mainstream did not occur in 2007 because of strong turbulence.The temperature of surface water in the Xiangxi Bay was generally higher than the mainstream in the stratified period,but the temperature of bottom water was locally lower than the mainstream.Moreover,Xiangxi Estuary had the phenomena of subsurface flow,circulation flow in plane and elevation,showing very complex three-dimensional flow characteristics.Therefore,the results could provide scientific basis for safety management of ecological environment in Three Gorges Reservoir.