壁面湍流标度律的PIV实验研究  

PIV Experimental Research of the Scaling Law in Wall Turbulence

作　　者：张珂[1] 李万平[1] 

机构地区：[1]华中科技大学土木工程与力学学院,湖北武汉430074

出　　处：《实验力学》2008年第6期549-556,共8页Journal of Experimental Mechanics

基　　金：国家自然科学基金资助项目(10372033)

摘　　要：利用高分辨率、高帧率PIV系统对湍流边界层内的自相似标度律在不同的壁面距离的具体表达形式进行了实验研究。在动量损失雷诺数(Reθ=2167)下测量平板湍流边界层内的二维瞬时速度场。应用小波分析和传统统计学方法,在垂直于平板的平面内,对不同法向位置的自相似的标度律的具体形式及其随尺度的变化情况进行考察,并与已知的She-leveque(简称SL)标度律进行比较分析。结果表明,越接近壁面,结构函数的概率密度曲线尾部越宽,表现出逐渐增强的间歇性;并且随着壁面距离的减小,ESS标度律曲线与SL标度律曲线之间的差别也就越大,而新形式标度律曲线则与SL标度律曲线的差别逐渐减小。在提取的结构尺度一样时,结构函数的标度指数随法向位置的不同变化不大,但是随着提取结构尺度的增加,两种形式的标度律适用的尺度范围也在逐渐增大。Expression form of the self-similarity scaling law in turbulent boundary layer at different distances was experimentally studied by using high-resolution, high-frame rate Particle-Image Velocimetry （PIV） system. Two-dimensional instantaneous velocity field was measured in a flat turbulent boundary layer with momentum thickness Reynolds number Reθ = 2167. While in the plane perpendicular to the flat and at different wall distances, the forms and its variation with scale of Extended Self Similarity （ESS） were studied and compared with She-leveque （SL） scaling law based on wavelet and traditional statistic methods. Results show that closer to the wall, the curve tail of probability density function becomes wider, which indicates more and more obvious intermittency. Along with the wall distance decrease, distinction between the scaling exponents of ESS and SL increases; while the difference between scaling exponents of new form and SL scaling law decreases. The change of structure function scaling exponents is small when same structure scale is extracted by wavelet at different wall distance. But as extracted structure scale increase, the application range of the two forms scaling law increases.

关 键 词：湍流边界层 概率密度函数 PIV(Particle-Image Velocimetry粒子图像测速仪) 标度律 

分 类 号：O357[理学—流体力学]