基于EFDC模型滇池外海水环境仿真研究

发布时间：2018-05-31 01:44

  本文选题：EFDC模型 + 水动力　； 参考：《浙江大学》2017年硕士论文

【摘要】：滇池是我国西南地区的第一大淡水湖,其发展状况与昆明市的发展息息相关。湖泊的水动力过程是水环境研究的基础。本文以2014年的数据为基础,利用EFDC建立滇池外海水动力模型,对滇池外海的流场、水温、水位、污染物的迁移扩散等进行模拟,结果如下:1)对比二维水动力模型和三维水动力模型的风生流模拟结果,发现三维水动力模型模拟四层以上结果趋于收敛,其模拟结果更合理。2)滇池外海的流场在绝大部分区域内受风的驱动影响,在河口位置受河流的驱动影响。受常年西南风的作用,滇池外海流场以逆时针方向的环流为主。滇池外海相对水位(滇池实际水位=相对水位+1871.5m)常年保持在14.9m左右。春季水位较高,可达15.1m。在夏季和秋季水位较低,最低可达14.7m。影响滇池水位变化的因素主要是出入湖流量。风对湖泊的流场和水位影响较大,风向的变化会引起湖水流向和湖体水位分布的变化。风速的变化则会引起湖体流场的流速和最大水位差的变化。3)滇池常年平均水温在16℃左右,最高水温在25℃左右。影响湖体温度变化的敏感参数主要是对流热传递相关系数RCHC和蒸发热传递相关系数REVC。滇池表层水温和底层水温之间存在分层现象,且最大温度梯度可达1.1℃/m,分层现象在夏秋两季较为明显。4)在滇池外海,污染物的迁移扩散路径主要与湖体流场有关,同时存在横向扩散。在设置三种降解速率的降解系数后,污染物的迁移扩散范围基本一致,但污染物的衰减和降解系数关系较大。通过对滇池外海进行水动力模拟发现:水位和流场是湖体的水动力过程中最重要的两个因素。外界的风对水位和流场的变化影响较大。通过全面了解滇池外海的水动力过程、温度变化、物质的迁移转化规律等,为今后的泥沙和水质研究提供理论支持。
[Abstract]:Dianchi Lake is the largest freshwater lake in southwest China, and its development is closely related to the development of Kunming City. The hydrodynamic process of lakes is the basis of the study of water environment. Based on the data of 2014, the hydrodynamic model of Dianchi Lake is established by using EFDC, and the flow field, water temperature, water level, pollutant migration and diffusion are simulated. The results are as follows: (1) comparing the results of wind induced flow simulation between two dimensional hydrodynamic model and three dimensional hydrodynamic model, it is found that the simulation results of three dimensional hydrodynamic model tend to converge over four layers. The simulation results are more reasonable. 2) the current field outside Dianchi Lake is driven by wind in most areas and by rivers in estuaries. Due to the effect of the annual southwest wind, the current field of the Dianchi Lake is dominated by the counter-clockwise circulation. The relative water level of Dianchi Lake (actual water level = relative water level of Dianchi Lake 1871. 5m) is kept at about 14. 9m all year round. The spring water level is relatively high, reaching 15.1m. The water level is lower in summer and autumn, and the lowest level is 14.7 m. The main factor influencing the water level of Dianchi Lake is the discharge of the lake. The wind has a great influence on the flow field and water level of the lake, and the change of wind direction will cause the change of the water flow direction and the water level distribution of the lake body. The variation of wind speed will cause the change of flow velocity and maximum water level difference of lake body. 3) the annual average water temperature of Dianchi Lake is about 16 鈩，

本文编号：1957798