JZUS - Journal of Zhejiang University SCIENCE

Journal of Zhejiang University SCIENCE A 2015 Vol.16 No.4 P.265-278

Effect of thermal stratification on interflow travel time in stratified reservoir

Author(s): Xiao-feng Zhang, Shi Ren, Jun-qing Lu, Xin-hua Lu
Affiliation(s): State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; more
Corresponding email(s): renshi@whu.edu.cn
Key Words: Interflow, Travel time, Stratification, Buoyancy frequency, Renormalization group (RNG) k-( model

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Abstract: This study is focused on the impact of thermal stratification on interflow travel time. A quantitative relation between buoyancy frequency and interflow travel time is theoretically derived based on the Bernoulli principle of energy conservation. Experiments and numerical simulations are carried out to validate the applicability of the proposed relation. For experiments, interflow movement is successfully detected in a small-depth water tank by releasing a denser flow into a temperature stratification environment. For numerical simulations, a vertical 2D renormalization group (RNG) k-( model is developed to simulate the interflow. The results both of the experiments and of the numerical simulations verify our proposed theory. The derived analytic relation is useful for the prediction of contaminant travel time in reservoirs and in assisting pollution control.

温度分层对于污染物在水库中运行时间的影响

目的：水库存在的温度分层导致入流能够形成表层流、间层流或者底层流。探讨温度分层的强弱对于污染物以间层流方式运动时在水库中滞留时间的影响。
创新点：1. 通过伯努利能量方程，推导出分层强度与间层流运动时间的关系；2. 建立试验模型，成功模拟间层流运动。
方法：1. 通过理论推导，得到温度分层的强度越大，间层流运动时间越短（公式13）；2. 在实验室中模拟不同温度分层强度下的间层流运动，验证理论推导的关系式（图7）；3. 通过数值模拟技术，模拟温度分层存在时的间层流运动，进一步验证温度分层强度与间层流运动时间之间的关系（图12）。
结论：1. 温度分层的存在会导致入流在分层水体中形成不同形态的流动；2. 温度分层强度的增加会导致间层流在分层水体中运动时间变短；3. 入流形成间层流方式的不同对于分层强度与间层流运行时间之间的关系没有影响。

关键词：温度分层；间层流；分层强度；浮力频率；运动时间

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温度分层对于污染物在水库中运行时间的影响

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