Pressure statistics and fine vortex structure in Turbulence

采用电容传声器和压阻式传感器测量了湍流射流中的压力脉动。从Kolmogorov普适标度的角度讨论了归一化压力谱的幂律指数和比例常数。在600这些雷诺数远大于那些在速度波动，以实现柯尔莫哥洛夫标度。谱常数不是普适的，而是依赖于雷诺数。将实测压力PDF与直接数值模拟进行比较，寻求新的方法和改进的测量技术。本研究采用小型传感器和麦克风同时测量了湍流边界层中的静压和壁压。所得结果可总结如下。（1）用平均压力分布求取垂直速度分量的均方根值。 ...更多信息 v^+的峰值位置是雷诺数的函数，y_p^+=0.00135乘以R_θ ^1.42。（2）壁面压力的均方根，用内变量归一化，表示R_θ的增函数; p_rms^+ Δ R_θ ^0.28。这一趋势与DNS的结果相似。（3）静压r.m.s.的分布，穿过边界层的p_rms^+没有显示雷诺数的标度。如果p_rms^+在对数区域内取平均值，则其雷诺数依赖性近似为幂律; p_rms^+<$R_θ ^0.32。这种雷诺数依赖性比流向速度或垂直速度分量强得多。（4）壁面压力与边界层静压的相关性为正值。当R_θ>7000时，若将距壁面的距离用Δ归一化，则相关系数的分布不受雷诺数的影响。(5)In相对于流向速度u，静压的均方根用ρ u_rms ^[2]换算。在内部区域，p_rms/ρu_rms^2的比值为1的数量级。压力与流向速度的相关性表明，在y/Δ=0.05和y/Δ= 0.2时，压力和流向速度分别出现极小值和极大值。在外部区域中，0.25<y/Δ，相关性变为负。在DNS中观察到这些趋势。少

Pressure fluctuation was measured in a turbulent jet using a condenser microphone and piezoresistive transducer. The power-law exponent and proportional constant of normalized pressure spectrum are discussed from the standpoint of Kolmogorov universal scaling. The clear power-law with scaling exponent close to -7/3 was confirmed in the range of 600<R_λ. These Reynolds numbers are much larger than those in velocity fluctuation to achieve Kolmogorov scaling. The spectral constant is not universal but depends on Reynolds numbers. Measured pressure PDFs are compared with direct numerical simulation.New methods and improved measurement techniques are thus sought for. In this study, both static pressure and wall pressure in turbulent boundary layers have been measured simultaneously by using small transducer and microphone. Obtained results may be summarized as follows.(1)The root mean square of vertical velocity component is evaluated by means of mean pressure distribution The profile is su … More fficiently agree with the result obtained by direct v-component velocity measurement.The peak location of v^+ is scaled as a function of Reynolds number ; y_p^+=0.00135 times R_θ^1.42.(2)Root mean square of wall pressure, normalized by inner variable, indicates an increasing function of R_θ ; p_rms^+∝R_θ^0.28. This trend is similar with the result by DNS.(3)The distribution of static pressure r.m.s., p_rms^+, across the boundary layer does not show the Reynolds number scaling. If p_rms^+ is averaged within the log-region, its Reynolds number dependence is approximated by the power-law ; p_rms^+∝R_θ^0.32. This Reynolds number dependence is much stronger than that of stream-wise velocity or vertical velocity component.(4)The correlation between wall and static pressure across the boundary layer indicates the positive value. The distribution of correlation coefficient does not show the Reynolds number dependence if the distance from the wall is normalized by Δ for R_θ>7000.(5)In relation to streamwise velocity u, the root mean square of static pressure is scaled by ρu_rms^2. The ratio p_rms/ρu_rms^2 is the order of 1 in the inner region. The correlation between the pressure and streamwise velocity indicates the local minimum and maximum value at y/Δ=0.05 and y/Δ=0.2,respectively. In the outer region, 0.25<y/Δ, the correlation becomes negative. These trends are observed in DNS. Less