The traditional quasi-steady friction models are proved to be inaccurate in transient pipe flow because they underestimate friction losses in transients.

在液体管道瞬变流计算中，传统的拟恒定摩阻模型不能准确描述瞬变流的真实物理现象。

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This paper gives, from the energy equation for rapidly varied flow, the equations for the calculation of the curve of equal cavitation number in consideration of friction losses.

本文在考虑水流阻力的情况下，提出计算等空化数曲线的方程组，并给出电算程序。

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Pipe friction is the resistance to flow caused by the pipe. As a general principle, it is better to use the largest practical pipe size to avoid losses in pump performance.

管道摩擦力是指由管道引起的流动阻力，作为一个常用原则，最好是使用最大的实用的管道尺寸以避免在水泵性能方面的损失。

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But smoother increases in marginal tax rates, as under current law, create less economic friction, and fewer deadweight losses, then those with a number of peaks and valleys.

FORBES: Nate Silver: A Minimum Tax On The Wealthy Poses Implementation Problems