The influence of peak-locking errors on turbulence statistics computed from PIV ensembles
The influence of peak-locking errors on turbulence statistics computed from PIV ensembles
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DOI：
10.1007/s00348-003-0754-2
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发表时间：
2004-03-01
影响因子：
2.4
通讯作者：
Christensen, KT
中科院分区：
文献类型：
--
作者：
Christensen, KT
考虑了峰值锁定误差对根据 PIV 数据集合计算的湍流统计的影响。 PIV 测量是在湍流通道流的流向壁法线平面中进行的。 PIV 图像以三种不同的方式进行询问，生成具有绝对、中等和最小峰值锁定的速度场集合。对所有三个数据集合计算的湍流统计表明，除了平均速度剖面外，单点统计中对峰值锁定的普遍敏感性。峰值锁定误差会传播到速度波动中，当存在严重峰值锁定时，会导致单点统计数据不准确。还发现流向速度和壁面法向速度的多点相关性受到严重峰值锁定水平的影响。由 PIV 时间延迟定义的测量位移范围似乎会影响峰值锁定误差对湍流统计的影响。较小的位移范围，特别是那些产生幅度小于一像素的位移波动的位移范围，在存在峰值锁定的情况下会产生不准确的湍流统计数据。
The influence of peak-locking errors on turbulence statistics computed from ensembles of PIV data is considered. PIV measurements are made in the streamwise-wall-normal plane of turbulent channel flow. The PIV images are interrogated in three distinct ways, generating ensembles of velocity fields with absolute, moderate, and minimal peak locking. Turbulence statistics computed for all three ensembles of data indicate a general sensitivity to peak locking in the single-point statistics, except for the mean velocity profile. Peak-locking errors propagate into the fluctuations of velocity, rendering single-point statistics inaccurate when severe peak locking is present. Multi-point correlations of both streamwise and wall-normal velocity are also found to be influenced by severe levels of peak locking. The displacement range of the measurement, defined by the PIV time delay, appears to affect the influence of peak-locking errors on turbulence statistics. Smaller displacement ranges, particularly those that produce displacement fluctuations that are less than one pixel in magnitude, yield inaccurate turbulence statistics in the presence of peak locking.