Velocity-defect scaling for turbulent boundary layers with a range of relative roughness
Velocity-defect scaling for turbulent boundary layers with a range of relative roughness
复制标题
具有一定相对粗糙度范围的湍流边界层的速度缺陷缩放
DOI：
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发表时间：
2005
期刊：
影响因子：
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通讯作者：
K. Flack
中科院分区：
文献类型：
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作者：
Jonathan S. Connelly;M. Schultz;K. Flack
Velocity profile measurements in zero pressure gradient, turbulent boundary layer flow were made on a smooth wall and on two types of rough walls with a wide range of roughness heights. The ratio of the boundary layer thickness (δ) to the roughness height (k) was 16≤δ/k≤110 in the present study, while the ratio of δ to the equivalent sand roughness height (ks) ranged from 6≤δ/ks≤91. The results show that the mean velocity profiles for all the test surfaces agree within experimental uncertainty in velocity-defect form in the overlap and outer layer when normalized by the friction velocity obtained using two different methods. The velocity-defect profiles also agree when normalized with the velocity scale proposed by Zagarola and Smits (J Fluid Mech 373:33–70, 1998). The results provide evidence that roughness effects on the mean flow are confined to the inner layer, and outer layer similarity of the mean velocity profile applies even for relatively large roughness.
