Suppression of galloping oscillations by injecting a high-frequency excitation

Abstract

Galloping is an aeroelastic instability which incites oscillatory motion of elastic structures when subjected to an incident flow. Because galloping is often detrimental to the integrity of the structure, many research studies have focused on investigating methodologies to suppress these oscillations. These include using passive energy sinks, altering the surface characteristics of the structure, actively changing the shape of the boundary layer through momentum injection and using feedback control algorithms. In this paper, we demonstrate that the critical flow speed at which galloping is activated can be substantially increased by subjecting the galloping structure to a high-frequency non-resonant base excitation. The average effect of the high-frequency excitation is to produce additional linear damping in the slow response which serves to suppress the galloping instability. We study this approach theoretically and demonstrate its effectiveness using experimental tests performed on a galloping cantilevered structure. It is demonstrated that the galloping speed can be tripled in some experimental cases. This article is part of the theme issue ‘Vibrational and stochastic resonance in driven nonlinear systems (part 2)’.

Vibrational and stochastic resonances in driven nonlinear systems: part 2

“…These include a Brownian particle confined in a structural cavity [ 25 , 26 ], coupled neuron-astrocyte [ 27 ] systems and neural networks [ 28 , 29 ]. Part 2 also presents articles in four application domains: image perception [ 6 ], energy harvesting [ 8 ], control of aerodynamic instability [ 12 ], and vibrational machines and devices [ 30 ].…”

“… The response of a bistable energy harvester to different excitations: the harvesting efficiency and links with stochastic and vibrational resonance, by Khovanov [ 8 ]. Suppression of galloping oscillations by injecting a high-frequency excitation, by Alhadidi et al [ 12 ]. Energy and frequency ripple in devices with inertial excitation of oscillations.…”

“…Suppression of galloping oscillations by injecting a high-frequency excitation, by Alhadidi et al [ 12 ].…”

“…Alhadidi et al [ 12 ] introduce a novel approach for suppressing galloping oscillations over a wide range of flow velocities that is capable of inducing them. The authors demonstrate, both theoretically and experimentally, that a high-frequency non-resonant base excitation can have this desirable effect.…”

“…It may include multiple frequencies, the simplest form being a bi-harmonic/dual-frequency driving force, and is often engineered to act as a control input with the aim of achieving, e.g. the general improvement of system performance [3], amplification and detection of weak signal inputs [4][5][6], enhancement of operating conditions and efficiency [7,8], control of the ion mean flux and ion energy in plasmas due to electrical asymmetry effect (EAE) [9][10][11], control of aerodynamic instabilities [12], particle excitation in magnetic particle imaging (MPI) [13,14], design of logic gates [15] as well as the control and annihilation of chaos and coexisting attractors [16]. It has been established that these applications are connected to a plethora of dynamical phenomena induced by driving forces, yielding insights into a diversity of microscopic and macroscopic processes as enumerated in a very recent review by Vincent & Kolebaje [2].…”