论文标题
基于小波的分解分析，用于统计稳定的和时间变化的流量
Wavelet-based resolvent analysis for statistically-stationary and temporally-evolving flows
论文作者
论文摘要
这项工作介绍了分解分析的公式，该分析使用小波转换而不是傅立叶变换。这允许除统计平稳流以外，还可以将解析分析扩展到具有非平稳手段的湍流。该公式的最佳分解模式对应于线性化的Navier-Stokes运算符最大程度地放大的潜在时间频率结构。我们验证了该方法的湍流通道流，并表明基于小波和基于傅立叶的分解分析对于统计平稳的流量等效。然后，我们应用基于小波的分解分析来研究湍流通道流的缓冲层中的瞬态生长机理，通过在时间和频率上窗口窗口窗口。该方法还应用于暂时变化的平行剪切流，例如振荡边界层和三维通道流，其中横向压力梯度在通道中呈现了完全发达的湍流。
This work introduces a formulation of resolvent analysis that uses wavelet transforms rather than Fourier transforms in time. This allows resolvent analysis to be extended to turbulent flows with non-stationary means in addition to statistically-stationary flows. The optimal resolvent modes for this formulation correspond to the potentially time-transient structures that are most amplified by the linearized Navier-Stokes operator. We validate this methodology for turbulent channel flow and show that the wavelet-based and Fourier-based resolvent analyses are equivalent for statistically-stationary flows. We then apply the wavelet-based resolvent analysis to study the transient growth mechanism in the buffer layer of a turbulent channel flow by windowing the resolvent operator in time and frequency. The method is also applied to temporally-evolving parallel shear flows such as an oscillating boundary layer and three-dimensional channel flow, in which a lateral pressure gradient perturbs a fully-developed turbulent flow in a channel.
