Optimized Waveforms for Feedback Control of Vortex Shedding

Joe, Won Tae; Colonius, Tim; MacMynowski, Douglas G.

doi:10.1007/978-3-642-11735-0_25

Cited by 5 publications

(12 citation statements)

References 16 publications

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“…Recent studies have also documented the effect of the waveform on performance. It appears that periodic but pulsatile actuation or modulated highfrequency sinusoidal oscillation can produce performance equal to or greater than sinusoidal actuation at the same frequency [26,27,[29][30][31]. Indeed, it appears that pulses with as low a duty cycle as 5 per cent can be effective [27].…”

Section: (B) Actuated Flowsmentioning

confidence: 99%

Control of vortex shedding on two- and three-dimensional aerofoils

Colonius

Williams

2011

Phil. Trans. R. Soc. A.

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We review and expand on the control of separated flows over flat plates and aerofoils at low Reynolds numbers associated with micro air vehicles. Experimental observations of the steady-state and transient lift response to actuation, and its dependence on the actuator, aerofoil geometry and flow conditions, are discussed and an attempt is made to unify them in terms of their excitation of periodic and transient vortex shedding. We also examine strategies for closed-loop flow and flight control using actuation of leading-edge vortices.

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Section: (B) Actuated Flowsmentioning

confidence: 99%

Control of vortex shedding on two- and three-dimensional aerofoils

Colonius

Williams

2011

Phil. Trans. R. Soc. A.

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“…and used in many studies (e.g. Taira & Colonius 2007;Colonius & Taira 2008;Ahuja & Rowley 2010;Joe et al 2010;Joe, Colonius & MacMynowski 2011;Ma et al 2011;Tu & Rowley 2012;Brunton et al 2013Brunton et al , 2014Choi, Colonius & Williams 2015;Flinois & Colonius 2015) so only an overview of the formulation of this code is given here. The reader is referred to the cited studies and the references therein for further details.…”

Section: Numerical Set-upmentioning

confidence: 99%

“…These usually target specific flow features and can thus be very powerful (e.g. Pastoor et al 2008;Joe, Colonius & MacMynowski 2010). Unfortunately, for most flows of interest, even a good understanding of the flow physics is not sufficient to guide the design of effective controllers.…”

mentioning

confidence: 99%

“…This approach can also be used as an off-line adjoint-based optimisation technique if applied to the full (potentially nonlinear) Navier-Stokes equations (e.g. Bewley, Moin & Temam 2001;Protas & Styczek 2002;Joe et al 2010;Flinois & Colonius 2015). In this case, the results are useful for revealing effective control mechanisms, which can for instance be exploited using intuition-based controllers (e.g.…”

mentioning

confidence: 99%

“…In this case, the results are useful for revealing effective control mechanisms, which can for instance be exploited using intuition-based controllers (e.g. Joe et al 2010).…”

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confidence: 99%

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Feedback control of unstable flows: a direct modelling approach using the Eigensystem Realisation Algorithm

Flinois

Morgans

2016

J. Fluid Mech.

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Obtaining low-order models for unstable flows in a systematic and computationally tractable manner has been a long-standing challenge. In this study, we show that the Eigensystem Realisation Algorithm (ERA) can be applied directly to unstable flows, and that the resulting models can be used to design robust stabilising feedback controllers. We consider the unstable flow around a D-shaped body, equipped with body-mounted actuators, and sensors located either in the wake or on the base of the body. A linear model is first obtained using approximate balanced truncation. It is then shown that it is straightforward and justified to obtain models for unstable flows by directly applying the ERA to the open-loop impulse response. We show that such models can also be obtained from the response of the nonlinear flow to a small impulse. Using robust control tools, the models are used to design and implement both proportional and H ∞ loop-shaping controllers. The designed controllers were found to be robust enough to stabilise the wake, even from the nonlinear vortex shedding state and in some cases at off-design Reynolds numbers.

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