Qiao Z X, Zhou Y, Wu Z
Institute for Turbulence-Noise-Vibration Interaction and Control, Harbin Institute of Technology, Shenzhen Campus, Shenzhen, People's Republic of China.
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
Proc Math Phys Eng Sci. 2017 Jun;473(2202):20170038. doi: 10.1098/rspa.2017.0038. Epub 2017 Jun 28.
This work explores experimentally the control of a turbulent boundary layer over a flat plate based on wall perturbation generated by piezo-ceramic actuators. Different schemes are investigated, including the feed-forward, the feedback, and the combined feed-forward and feedback strategies, with a view to suppressing the near-wall high-speed events and hence reducing skin friction drag. While the strategies may achieve a local maximum drag reduction slightly less than their counterpart of the open-loop control, the corresponding duty cycles are substantially reduced when compared with that of the open-loop control. The results suggest a good potential to cut down the input energy under these control strategies. The fluctuating velocity, spectra, Taylor microscale and mean energy dissipation are measured across the boundary layer with and without control and, based on the measurements, the flow mechanism behind the control is proposed.
这项工作基于压电陶瓷致动器产生的壁面扰动，通过实验探索了平板上湍流边界层的控制方法。研究了不同的方案，包括前馈、反馈以及前馈与反馈相结合的策略，旨在抑制近壁高速事件，从而降低表面摩擦阻力。虽然这些策略实现的局部最大减阻效果略低于开环控制的对应效果，但与开环控制相比，相应的占空比大幅降低。结果表明，在这些控制策略下具有降低输入能量的良好潜力。在有控制和无控制的情况下，对边界层内的脉动速度、频谱、泰勒微尺度和平均能量耗散进行了测量，并基于这些测量结果提出了控制背后的流动机制。
