Small Silicon Pressure Transducers for Space-Time Correlation Measurements in a Flat Plate Boundary Layer
Small Silicon Pressure Transducers for Space-Time Correlation Measurements in a Flat Plate Boundary Layer
复制标题
用于平板边界层中时空相关性测量的小型硅压力传感器
DOI：
10.1115/1.2817780
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发表时间：
1996
影响因子：
2
通讯作者：
G. Stemme
中科院分区：
文献类型：
--
作者：
L. Löfdahl;Edvard Kälvesten;G. Stemme
用硅基压力传感器测量了Re θ = 5072的二维平板边界层中的湍流壁面压力脉动。膜片的边长分别为100 μm（d + = 7.2）和300 μm（d + = 21.6），边界层厚度与膜片边长之比为240，波数小于10个粘性单位的涡的分辨率。功率谱测量的频率范围为13 Hz < f < 13 kHz。在外部和内部变量中缩放，示出了频谱的中频部分和高频部分之间的明显重叠区域。在该重叠区域中，发现斜率为ω -1，而在高频部分中，斜率为ω -5。在纵向和横向的相关测量进行了比较，与其他调查。纵向时空的相关性，包括高频率范围，表明平流速度的顺序的一半的自由速度。纵向相关性的宽带滤波表明，频谱的高频部分与来自边界层内部的较小涡流有关，导致相关性降低。
Silicon based pressure sensors have been used to measure turbulent wall-pressure fluctuations in a two-dimensional flat plate boundary layer, Re θ = 5072. The side lengths of the diaphragms were 100 μm (d + = 7.2 ) and 300 μm (d + = 21.6), giving a ratio of the boundary layer thickness to the diaphragm side length of the order of 240 and a resolution of eddies with wave numbers less than ten viscous units. Power spectra were measured for the frequency range 13 Hz < f < 13 kHz. Scaled in outer and inner variables a clear overlap region between the mid and high frequency parts of the spectrum is shown. In this overlap region the slope was found to be ω -1 , while in the high frequency part it was ω -5 . Correlation measurements in both the longitudinal and transversal directions were performed and compared to other investigations. Longitudinal space time correlations, including the high frequency range, indicated an advection velocity of the order of half the freestream velocity. A broad band filtering of the longitudinal correlation showed that the high frequency part of the spectrum is associated with the smaller eddies from the inner part of the boundary layer, resulting in a reduction of the correlation.