Comprehensive shear stress analysis of turbulent boundary layer profiles
Comprehensive shear stress analysis of turbulent boundary layer profiles
复制标题
湍流边界层剖面的综合剪应力分析
DOI：
10.1017/jfm.2019.673
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发表时间：
2019
影响因子：
3.7
通讯作者：
Schultz, Michael P.
中科院分区：
文献类型：
--
作者：
Womack, Kristofer M.;Meneveau, Charles;Schultz, Michael P.
出于需要准确测定壁面剪应力的轮廓测量在湍流边界层流动，总剪应力平衡进行了分析，并重新制定了几个完善的半经验关系。该分析强调了即使在名义上为零的压力梯度边界层中，小压力梯度也会对从数据推导出的参数产生显着影响。使用综合剪应力平衡与对数律方程，它表明，摩擦速度，粗糙度长度和零平面位移可以确定只有速度和湍流剪应力分布测量在一个单一的流向位置名义上为零压力梯度湍流边界层。所提出的分析湍流光滑和粗糙壁实验数据的应用表明，摩擦速度的确定与力平衡（约1%-4%）的准确性。此外，从以前的研究应用到边界层数据提供了明确的证据，经常引用的直接测量的摩擦速度（例如，使用力平衡）和那些来自传统的总剪应力方法之间的差异可能是由于一个固定的横截面设施所施加的小的有利的压力梯度。建议的综合剪切应力分析可以解释这些小的压力梯度，并允许更准确的边界层壁面剪切应力或摩擦速度的确定，使用通常可用的平均速度和剪切应力分布数据从一个单一的流向位置。
Motivated by the need for accurate determination of wall shear stress from profile measurements in turbulent boundary layer flows, the total shear stress balance is analysed and reformulated using several well-established semi-empirical relations. The analysis highlights the significant effect that small pressure gradients can have on parameters deduced from data even in nominally zero pressure gradient boundary layers. Using the comprehensive shear stress balance together with the log-law equation, it is shown that friction velocity, roughness length and zero-plane displacement can be determined with only velocity and turbulent shear stress profile measurements at a single streamwise location for nominally zero pressure gradient turbulent boundary layers. Application of the proposed analysis to turbulent smooth- and rough-wall experimental data shows that the friction velocity is determined with accuracy comparable to force balances (approximately 1 %–4 %). Additionally, application to boundary layer data from previous studies provides clear evidence that the often cited discrepancy between directly measured friction velocities (e.g. using force balances) and those derived from traditional total shear stress methods is likely due to the small favourable pressure gradient imposed by a fixed cross-section facility. The proposed comprehensive shear stress analysis can account for these small pressure gradients and allows more accurate boundary layer wall shear stress or friction velocity determination using commonly available mean velocity and shear stress profile data from a single streamwise location.
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影响因子：
4.6
作者：
Brzek, Brian;Cal, Raul Bayoan;Castillo, Luciano
通讯作者：
Castillo, Luciano
影响因子：
3.7
作者：
A. Perry;J. D. Li
通讯作者：
A. Perry;J. D. Li
根据平均速度和雷诺剪应力分布确定壁剪应力
影响因子：
2
作者：
R. Volino;M. Schultz
通讯作者：
M. Schultz
影响因子：
3.7
作者：
M. Schultz;K. Flack
通讯作者：
M. Schultz;K. Flack
影响因子：
3.7
作者：
I. Castro
通讯作者：
I. Castro