Reference : Triggering mechanisms of limit cycle oscillations due to aeroelastic instability
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Physics
Engineering, computing & technology : Mechanical engineering
http://hdl.handle.net/2268/18324
Triggering mechanisms of limit cycle oscillations due to aeroelastic instability
English
Lee, Y. S. [> >University of Illinois at Urbana-Champaign, USA> > Department of Mechanical and Industrial Engineering, > > >]
Vakakis, Alexander F. [[National Technical University of Athens (Greece) > Division of Mechanics > > >]
Bergman, Lawrence A. [>> >University of Illinois at Urbana-Champaign, USA> > > >Department of Mechanical and Industrial Engineering, > > >]
McFarland, D. Michael [>University of Illinois at Urbana-Champaign, USA> > > >Department of Mechanical and Industrial Engineering, > > >]
Kerschen, Gaëtan mailto [Université de Liège - ULg > Département d'aérospatiale et mécanique > Laboratoire de structures et systèmes spatiaux >]
Dec-2005
Journal of Fluids & Structures
Academic Press
21
485–529
Yes (verified by ORBi)
International
0889-9746
London
United Kingdom
[en] limit cycle oscillation (LCO) ; aerociastic instability ; numerical continuation ; triggering mechanism ; resonance capture
[en] We show that a cascade of resonance captures constitutes the triggering mechanism of limit cycle oscillations (LCOs) due to aeroelastic instability of rigid wings in flow. We consider a two-degree-of-freedom (2-dof) wing model in subsonic flow with cubic nonlinear stiffnesses at the support. Under the assumption of quasi-steady aerodynamics, we apply a complexification/averaging technique to express the dynamics of fluid-structure interactions in terms of three fast-frequency components; these are the two linear natural frequencies corresponding to heave and pitch, and a superharmonic at three times the pitch frequency. Bifurcation analysis of the resulting set of modulation equations governing the slow dynamics is carried out via the method of numerical continuation, and reveals the different types of steady state motions realized as parameters vary. It turns out that the LCO triggering mechanism consists of a combination of different dynamic phenomena, taking place at three main stages or regimes: attraction to transient resonance captures (TRCs), escapes from these captures and, finally, entrapments into permanent resonance captures (PRCs). We examine numerically and analytically the dynamics at each of these stages by means of wavelet transform analysis, study of the evolution of appropriately defined phase variables in projections of the phase space of the dynamics, and analysis of instantaneous energy exchanges between the various nonlinear modes involved. The general conclusion is that an initial excitation of the heave mode by the flow acts as the triggering mechanism for the excitation of the pitch mode through nonlinear interactions resulting from the resonance captures and escapes. The eventual excitation of the pitch mode signifies the appearance of an LCO of the in-flow wing. (c) 2005 Elsevier Ltd. All rights reserved.
Researchers ; Professionals ; Students
http://hdl.handle.net/2268/18324
10.1016/j.jfluidstructs.2005.08.011

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