Experimental measurement of wall shear stress in strongly disrupted flows
Experimental measurement of wall shear stress in strongly disrupted flows
复制标题
强扰动流中壁面剪应力的实验测量
DOI：
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复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
O. Buxton
中科院分区：
文献类型：
--
作者：
E. Rodríguez;P. Bruce;O. Buxton
摘要在各种低孔隙率壁装、单尺度和多尺度栅栏产生的强烈破坏情况下，测量了平均和波动的壁面剪应力。这些网格产生高度湍动的尾迹，与壁面边界流相互作用，改变了壁面剪应力特性。测量方法首先在自然增长的零压力梯度湍流边界层上进行了验证，平均剪应力的外推和直接测量的精度分别为1%和4%。与波动的均方根水平相关的不确定度好于2%，这使得测量源自不同围栏的微小变化成为可能。此外，还测量了概率密度函数和谱，为进一步了解流动物理提供了依据。在网格+TBL破坏情况下的剪应力测量表明，即使在最严重的破坏情况下，流动特性和湍流机制在远离网格的地方也保持不变。然而，对于不同的网格，发现了不同的均方根水平的波动。对概率密度函数的研究似乎表明，流动的内部和外部区域之间存在不同程度的相互作用。
ABSTRACT Mean and fluctuating wall shear stress is measured in strongly disrupted cases generated by various low-porosity wall-mounted single- and multi-scale fences. These grids generate a highly turbulent wake which interacts with the wall-bounded flow modifying the wall shear stress properties. Measurement methods are validated first against a naturally growing zero pressure gradient turbulent boundary layer showing accuracies of 1% and 4% for extrapolation and direct measurement of the mean shear stress respectively. Uncertainty associated with the root mean square level of the fluctuations is better than 2% making it possible to measure small variations originating from the different fences. Additionally, probability density functions and spectra are also measured providing further insight into the flow physics. Measurement of shear stress in the disrupted cases (grid+TBL) suggest that the flow characteristics and turbulence mechanisms remain unaltered far from the grid even in the most disrupted cases. However, a different root mean square level of the fluctuations is found for different grids. Study of the probability density functions seem to imply that there are different degrees of interaction between the inner and outer regions of the flow.
DOI：
10.48550/arxiv.1203.3714
发表时间：
2012
期刊：
--
影响因子：
--
作者：
Chernyshenko S
通讯作者：
Chernyshenko S
影响因子：
1.5
作者：
Laizet, S.;Vassilicos, J. C.
通讯作者：
Vassilicos, J. C.