超声速湍流边界层密度场特性

发布时间：2018-03-03 05:23

本文选题：超声速　切入点：湍流边界层　出处：《物理学报》2017年02期 　论文类型：期刊论文

【摘要】：本文采用基于纳米示踪平面激光散射技术的密度场测量方法,对Ma=3.0零压力梯度平板湍流边界层的密度场特性进行了实验研究,分析了边界层密度场的平均特性和脉动特性,并利用泰勒假设将空间信号转换为时域信号,对密度脉动的频谱特性进行了分析.研究发现,随着高度增加,边界层平均密度逐渐增大,但密度脉动仅在对数区内逐渐增大,在边界层外层却逐渐减小.密度脉动的概率密度函数在对数区内呈正态分布.从频谱特性可以发现,湍流边界层内部密度脉动具有丰富的脉动频率,最高达到MHz量级;在边界层近壁区和外层,密度脉动以低频分量为主;在对数区,高频分量与低频分量所占的比例基本相同.结合速度和密度同时测量发现,密度脉动与质量流量脉动在概率密度分布和频谱特性方面具有非常好的一致性,但与速度脉动相关性不大.超声速湍流边界层内部强烈密度脉动,及其与速度脉动的明显差别,是可压缩湍流边界层与不可压湍流边界层的显著区别之一.
[Abstract]:In this paper, the density field characteristics of the turbulent boundary layer of Ma=3.0 flat plate with zero pressure gradient are experimentally studied by using the density field measurement method based on nano-tracer plane laser scattering technique. The average and pulsating characteristics of the density field in the boundary layer are analyzed. The spectral characteristics of density pulsation are analyzed by using Taylor hypothesis to transform spatial signals into time domain signals. It is found that the average density of the boundary layer increases with the increase of height, but the density pulsation increases only in the logarithmic region. The probability density function of the density pulsation is normal distribution in the logarithmic region. From the spectrum characteristics, it can be found that the density pulsation in the turbulent boundary layer has abundant pulsation frequency, which reaches the MHz order of magnitude. In the near wall and outer layer of the boundary layer, the density pulsation is dominated by the low frequency component, and in the logarithmic region, the proportion of the high frequency component and the low frequency component is basically the same. Density pulsation and mass flow pulsation have very good consistency in probability density distribution and spectral characteristics, but have little correlation with velocity pulsation. It is one of the significant differences between compressible turbulent boundary layer and incompressible turbulent boundary layer.
【作者单位】：国防科学技术大学航天科学与工程学院;
【基金】：国家自然科学基金(批准号:11302256)资助的课题~~
【分类号】：O357.5;O354.3

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