Rough-wall boundary layers: mean flow universality
Rough-wall boundary layers: mean flow universality
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DOI：
10.1017/s0022112007006921
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发表时间：
2007-08
影响因子：
3.7
通讯作者：
I. Castro
中科院分区：
文献类型：
--
作者：
I. Castro
提出并讨论了在各种完全空气动力学粗糙表面上自然发展的边界层的平均流动剖面、表面摩擦和积分参数。动量厚度雷诺数Reθ扩展到超过47000的值，并且与以前的工作不同，粗糙度单元高度与边界层深度之比的范围非常广（0.03 0.5）。在假定平均速度剖面的通用双参数形式的基础上，与一些经典公式进行了比较，并与其他最近的测量结果进行了比较。结果表明，无论粗糙度的性质如何，前者的适当重写版本都可以用于折叠所有数据，除非表面非常粗糙，这意味着典型的粗糙度单元高度超过边界层动量厚度的约50%，对应于约$h/\delta\,{\ widdetilde{>}}\,0.2$。
Mean flow profiles, skin friction, and integral parameters for boundary layers developing naturally over a wide variety of fully aerodynamically rough surfaces are presented and discussed. The momentum thickness Reynolds number Reθ extends to values in excess of 47000 and, unlike previous work, a very wide range of the ratio of roughness element height to boundary-layer depth is covered (0.03 0.5). Comparisons are made with some classical formulations based on the assumption of a universal two-parameter form for the mean velocity profile, and also with other recent measurements. It is shown that appropriately re-written versions of the former can be used to collapse all the data, irrespective of the nature of the roughness, unless the surface is very rough, meaning that the typical roughness element height exceeds some 50% of the boundary-layer momentum thickness, corresponding to about $h/\delta\,{\widetilde{>}}\,0.2$.