The separation flow is three dimensional in hydraulic machine. The pressure gradient in cross direction produces secondary flow in boundary layer.

水力机械的分离为三维流动，三维流动的侧向压力梯度产生边界层的二次流动。

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Owing to its native feature and the influence by artificial exploitation, the shallow groundwater is vertical cross-flow supplement to medium layer groundwater.

由于含水系统本身特点及人工开采影响，浅层水对中层地下水垂直越流补给。

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The velocity amplitude distributions of the oscillatory flow outside the boundary layer are measured at seven cross-sections along the horizontal, the vertical, and the bent sections respectively.

对于水平直管段上底面及下底面各三个截面，测量了边界层内振荡流速的振幅分布及相位分布。

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