Low speed flutter and limit cycle oscillations of a two-degree-of-freedom flat plate in a wind tunnel

Abstract

Amandolese, X., et al., Low speed flutter and limit cycle oscillations of a two-degree-offreedom flat plate in a wind tunnel. Journal of Fluids and Structures (2013) ABSTRACTThis paper explores the dynamical response of a two-degree-of-freedom flat plate undergoing classical coupled-mode flutter in a wind tunnel. Tests are performed at low Reynolds number (Re ~ 2.5×10 4 ), using an aeroelastic set-up that enables high amplitude pitch-plunge motion.Starting from rest and increasing the flow velocity, an unstable behaviour is first observed at the merging of frequencies: after a transient growth period the system enters a low amplitude limit-cycle oscillation regime with slowly varying amplitude. For higher velocity the system transitions to higher-amplitude and stable limit cycle oscillations (LCO) with an amplitude increasing with the flow velocity. Decreasing the velocity from this upper LCO branch the system remains in stable self-sustained oscillations down to 85% of the critical velocity.Starting from rest, the system can also move toward a stable LCO regime if a significant perturbation is imposed. Those results show that both the flutter boundary and post-critical behaviour are affected by nonlinear mechanisms. They also suggest that nonlinear aerodynamic effects play a significant role. KEYWORDS

Large amplitude flow-induced oscillations and energy harvesting using a cyber-physical pitching plate

“…The value of π=2, predicted by the thin-airfoil theory is plotted with a black solid line. The present results compare well with previouslyreported data of Fage and Johansen (1927), Pelletier and Mueller (2000), and Amandolese et al (2013). A careful and highresolution measurement of the pitching moment at fixed angles is shown in Fig.…”

“…Our current ability to model large-amplitude oscillations due to fluid-structure instabilities remains insufficient, albeit a number of experimental studies reported in the archival literature (e.g., Dimitriadis and Li, 2009;Razak et al, 2011;Amandolese et al, 2013). Significant efforts have been made to elucidate the mechanism by which a classical linear flutter transforms into a complex bifurcation behavior that leads to violent oscillations induced by the dynamic stall phenomenon.…”

Passive control of the flutter instability on a two-degrees-of-freedom system with pseudoelastic shape-memory alloy springs.

“…These preliminary findings will be confronted to experiments in order to confirm the potential of the SMA as a passive device for controlling the flutter instability. Preliminary results with aeroelastic parameters fitted to the experiments reported in [9] show an important increase of Θ c so that the LCO amplitudes should be controlled on a larger range of flow velocities.…”

Fluid-structure interaction in long-span bridges

“…Also the decreasing trend with the increasing velocities has been pointed out by authors like Amandolese or Matsumoto [155,158,159]. According to this last reference, the plate is suffering a high-speed torsional flutter.…”

“…Caracoglia presents some of the proposed apparatuses and introduces a new one in [154]. Therefore, it is clear that this investigation line is far from being over, and many researchers work on it [147,150,155].…”