An experimental investigation of near-wall scale interactions in the presence of a deterministic forcing input is presented in this work. The external forcing input was generated by a wall-mounted piezoelectric (PZT) actuator, which directly introduces a dynamic perturbation into the near-wall cycle of turbulent boundary layer flow. The spectra of velocity fluctuations indicated that the fundamental forcing mode can be observed in all the perturbed cases and that the occurrence of high-order harmonics is dependent on the PZT perturbation amplitude. Under the strong forcing input, the fundamental forcing mode is influenced by large-scale structures through a high-degree amplitude modulation (AM) effect. More importantly, the phase-switching process was found for the high-order harmonics and small-scale turbulence, both of which are in phase with the forcing mode in $y^{+}\stackrel{<}{\sim \phantom{{}_x}}10$ and are switched to be out of phase in $20\stackrel{<}{\sim \phantom{{}_x}}{y}^{+}\stackrel{<}{\sim \phantom{{}_x}}50$. It was demonstrated that the forcing mode rearranges both the harmonics and small-scale turbulence in the near-wall region, as evidenced by the AM effect and phase relationship. In addition, the near-wall scale rearrangements were confirmed by the skewness cross-term distribution.

在这项工作中存在确定性强迫输入的情况下，近壁尺度相互作用的实验研究。外部强迫输入是由壁挂式压电（PZT）致动器产生的，该致动器将动态扰动直接引入湍流边界层流的近壁循环中。速度波动谱表明，在所有扰动情况下都可以观察到基本强迫模式，并且高次谐波的发生取决于PZT扰动幅度。在强强制输入下，基本强制模式会通过高幅度调制（AM）效应受到大型结构的影响。更重要的是，发现了针对高次谐波和小尺度湍流的相位切换过程，${ÿ}^{+}\stackrel{<}{〜\phantom{{}_X}}10$ 并切换为异相 $20\stackrel{<}{〜\phantom{{}_X}}{ÿ}^{+}\stackrel{<}{〜\phantom{{}_X}}50$。结果表明，强迫模式在近壁区域重新排列了谐波和小尺度湍流，这由AM效应和相位关系证明。另外，通过偏斜项分布确认了近壁尺度的重排。