The unsteady free water sheet flow in the rotating bucket of a Pelton turbine is a very complex flow that cannot be accurately simulated for lack of a numerical method.

冲击式水轮机水斗内非定常自由水膜的流动非常复杂，至今还没有足够精确的数值方法来模拟这种流动。

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Protection design for lower reaches of the Yellow River was once a difficult question due to high water head, various combinations of discharging structures, and complex flow pattern.

小浪底工程由于水头高、泄水建筑物组合多，水流流态十分复杂，下游防护设计是一难题。

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Simple flow chart view of the power are in fact water, steam cycle of flow in the flow control valve in the selection of simple and complex.

简单来看电力流程图实际上是水、蒸汽的循环流程，在此流程中选用控制阀既简单又复杂。

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