Flow resistance over fixed roughness elements
Flow resistance over fixed roughness elements
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固定粗糙度元素上的流阻
DOI：
10.1080/00221686.2010.540121
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发表时间：
2011
影响因子：
2.3
通讯作者：
N. Dharmasiri
中科院分区：
文献类型：
--
作者：
Shu‐Qing Yang;Yu Han;N. Dharmasiri
研究了粗糙边界上明渠和管道的流动阻力机理。与Einstein方法不同，本文将移动的床面边界剪应力求和原理推广到刚性边界。结果发现，该原则是有效的，以表示在所有的管流状态，主要涉及从层流到湍流的过渡，以及完全光滑和完全粗糙的湍流之间的摩擦系数。这项研究还评估了爱因斯坦关于表面摩擦力和形状阻力之间关系的概念。Nikuradse的实验数据被用来测试所获得的结果，表明上述方法产生的最佳协议与实验数据，相对于其他的摩擦系数公式在文献中可用。
The underlying mechanism of flow resistance in open channels and pipelines over rough boundary is investigated. Different from Einstein's method, this work extends the principle of boundary shear stress summation in a mobile bed to the rigid boundary. It is found that the principle is valid to express the friction factor in all pipe flow regimes, mainly concerning the transition from laminar to turbulent flows, and between fully smooth and fully rough turbulent flows. This research also evaluates the concept developed by Einstein regarding the relationship between skin friction and form drag. Experimental data of Nikuradse are used to test the obtained results, indicating that the above-mentioned method yields the best agreement with experimental data, relative to the other friction factor formulas available in the literature.