Physical model test and analysis of water temperature in large reservoirs
With the development of hydraulic engineering technology, a lot of large reservoirs have been built or will be built in China. Large depth, high capacity, and enormous economic benefit are brought by those large reservoirs. Meanwhile, ecological and environmental problem are more serious in large reservoirs than small ones because of water temperature stratification. In general, the strongest stratification appears in late spring and early summer for meteorologic condition and hydrodynamic condition. How to diminish negative effects of water temperature stratification by reservoir design or scientific operation is of great urgency and significance. However, little on-site observed data are available for reservoir stratification study because of difficulties of observation in deep water. We established a physical model to simulate the formation and development of water temperature stratification in late spring and early summer and compared water temperature differences along the vertical direction and longitudinal direction under different water release ways and water fluxes. The results show: (1) Water temperature vertical structure is very complicated. It can be thermocline-hypolimion structure, two thermoclines linked by a mixed layer, three thermoclines with different gradient, two thermoclines with different gradient and a hypolimion at bottom, and so on. All structures are resulted from characteristics of stratified flow and specific hydrodynamic conditions. (2) Vertical temperature difference depends on section locations, water flux, and outlet elevation. Mostly, vertical difference at upstream section is larger than downstream. The vertical temperature difference increases with water flux and the outlet elevation. The largest observed vertical difference is 4.15℃. (3) Longitudinal distribution has a close relation with depth, water flux, and outlet elevation. At surface and middle depth, the upstream temperature is higher than downstream. The difference rises with the increase of the water flux and the outlet elevation as well. At bottom the downstream temperature is higher than upstream in a certain period when outlet adopts surface one and water flux is large. (4) Temperature of discharged water is influenced by water flux and outlet elevation. Lower outlet elevation results in lower discharged water temperature, especially in the beginning period. The largest difference among the test cases is 3.5℃.
water temperature temperature stratification physical model large reservoir
Huatang Ren Jie He Jianxin Xia Zhaohui Yu
Department of Environmental science, Minzu University of China, Beijing, 100081, P. R. China
国际会议
The 3rd Biennial ISRS Symposium Achieving Healthy and Viable Rivers (ISRS)第3届国际河流大会
北京
英文
316-323
2013-08-05（万方平台首次上网日期，不代表论文的发表时间）