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长江上游金沙江、岷江上梯级电站的日调节作用对其下游河道水流运动产生影响,两江水流在宜宾交汇、叠加,两股非恒定水流的耦合使下游河道水流运动规律变得更为复杂。为确定长江干流叙渝段在上游干、支流梯级水库日调节影响作用下的最不利通航的水流条件,建立了兼顾计算精度、效率、稳定性的二维非恒定流数学模型,在确定岷江、金沙江非恒定流代表工况的基础上,数值模拟了下游河道水流参数变化规律。结果表明,洪水传播过程中存在明显的坦化现象,沿程李庄、泸州、朱沱测站水位变幅渐次降低,水流非恒定参数也呈沿程减小的趋势,下游河道水流的非恒定性主要受基流及流量变幅都较大的金沙江向家坝日调节过程影响;进而确定了金沙江、岷江最不利来流条件组合工况。
The daily regulation of the Jinsha and Cascade hydropower stations on the upper reaches of the Yangtze River has an impact on the waterway movement in the lower reaches of the Yangtze River. The coupling of the two water streams at Yibin, the superposition, and the two unsteady water flows make the movement of the downstream river more complicated. In order to determine the most unfavorable navigation conditions under the influence of upstream regulation of upstream and tributary reservoirs in the Syrian Section of the Yangtze River, a mathematical model of two-dimensional unsteady flow, which accounts for the accuracy, efficiency and stability of calculation, was established. On the basis of the unsteady flow representative of Jinsha River, the variation regularity of downstream flow parameters is simulated. The results show that there is a clear phenomenon of ozone in the process of flood propagation. The amplitude of water level of Li Zhuang, Luzhou and Zhu Tuo stations along the process gradually decreases. The unsteady flow parameters also show a decreasing trend along the river. It is mainly affected by the adjustment process of Xiangjiaba, Jinsha River, where the base flow and the flow rate fluctuate greatly, and then determines the combined working conditions of the most adverse flow conditions of the Jinsha and Minjiang Rivers.