scholarly journals Open-loop control of noise amplification in a separated boundary layer flow

2013 ◽  
Vol 25 (12) ◽  
pp. 124106 ◽  
Author(s):  
E. Boujo ◽  
U. Ehrenstein ◽  
F. Gallaire
Keyword(s):  
Boundary Layer ◽  
Boundary Layer Flow ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control ◽  
Layer Flow ◽  
Noise Amplification

scholarly journals Open-loop control of a separated boundary layer

2014 ◽  
Vol 342 (6-7) ◽  
pp. 403-409 ◽  
Author(s):  
Édouard Boujo ◽  
François Gallaire ◽  
Uwe Ehrenstein
Keyword(s):  
Boundary Layer ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control

scholarly journals Turbulent boundary layer under the control of different schemes

2017 ◽  
Vol 473 (2202) ◽  
pp. 20170038 ◽  
Author(s):  
Z. X. Qiao ◽  
Y. Zhou ◽  
Z. Wu
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
High Speed ◽  
Control Strategies ◽  
Local Maximum ◽  
Open Loop ◽  
Open Loop Control ◽  
Feed Forward ◽  
Loop Control ◽  
Combined Feed

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.

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