对流槽湍流涡旋结构特征的小波分析

为研究夹卷层的湍流特性，用对流槽模拟大气对流边界层并做湍流温度测量.能谱分析表明，混合层湍流谱幂律接近“-5/3”次律；而夹卷层湍流谱幂律有明显的分段特征.利用离散正交小波对其湍流脉动信号进行去噪和尺度分解，将原始信号分成均匀各向同性小尺度涡旋成分和大尺度涡旋成分，并对分解后的信号做能谱分析.结果表明，不论是在混合层还是在夹卷层，小涡都能很好地满足Kolmogorov的“-5/3”次律；而大尺度涡旋则在混合层和夹卷层中表现出不同的特征.

An analysis of convective boundary layer eddy structure in water tank by orthonormal wavelet

Using orthonormal wavelet transform, we make an analysis to experimental data of convective boundary layer turbulence in water tank, including multi-scale decomposition and high frequency noise removing. Spectrum analysis shows that turbulence in the mixed layer is very different from that in the entrainment zone. This difference may be caused by various characteristics of large scale elements in turbulence. While the small scale turbulence in both the mixed layer and the entrainment zone are similar, they are homogeneous and their spectra are satisfied with the Kolmogorov's -5/3 exponent law.