Abstract Aerodynamic performance of low-Reynolds number flyers, for a chord-based Reynolds number of 105 or below, is sensitive to wind gusts and flow separation. Active flow control offers insight into fluid physics as well as possible improvements in vehicle performance. While facilitating flow control by introducing feedback control and fluidic devices, major challenges of achieving a target aerodynamic performance under unsteady flow conditions lie on the high-dimensional nonlinear dynamics of the flow system. Therefore, a successful flow control framework requires a viable as well as accessible control scheme and understanding of underlying flow dynamics as key information of the flow system. On the other hand, promising devices have been developed recently to facilitate flow control in this flow regime. The dielectric barrier discharge (DBD) actuator is such an example; it does not have moving parts and provides fast impact on the flow field locally. In this paper, recent feedback flow control studies, especially those focusing on unsteady low-Reynolds number aerodynamics, are reviewed. As an example of an effective flow control framework, it is demonstrated that aerodynamic lift of a high angle-of-attack wing under fluctuating free-stream conditions can be stabilized using the DBD actuator and an adaptive algorithm based on general input–output models. System nonlinearities and control challenges are discussed by assessing control performance and the variation of the system parameters under various flow and actuation conditions. Other fundamental issues from the flow dynamics view point, such as the lift stabilization mechanism and the influence on drag fluctuation are also explored. Both potentiality and limitation of the linear modeling approach are discussed. In addition, guidelines on system identification and the controller and actuator setups are suggested.
Highlights ► Recent studies of feedback flow control at low-Reynolds numbers are reviewed. ► The impact of the DBD actuator on a high angle-of-attack wing is discussed. ► Unsteady aerodynamic forces of the wing are stabilized using an adaptive control algorithm. ► The flow–actuator system is analyzed based on the system identification (ID) approach. ► System nonlinearities and control challenges are explored based on the ID and control results.
Adaptive flow control of low-Reynolds number aerodynamics using dielectric barrier discharge actuator
Progress in Aerospace Sciences ; 47 , 7 ; 495-521
2011-01-01
27 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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