Coherence resonance in a nonlinear aeroelastic system.

Abstract

This study is a novel attempt to investigate and establish coherence resonance in a nonlinear aeroelastic system under additive Gaussian white noise. It offers a fresh perspective compared to the earlier studies in this field, which mostly focused on the undesirable disordered responses due to noise, while the present study explores the ability of noise to induce "order" in the system. The baseline deterministic model considered is a classical representative of a fluid-structure interaction system displaying subcritical Hopf bifurcation and is well-studied due to its engineering relevance. The interplay between the input noise and the nonlinearity has a profound impact on the dynamics, and at an optimum level of noise, the system exhibits nearly periodic, coherent oscillations. This is identified as the phenomenon of coherence resonance commonly exhibited by nonlinear systems, marked by a peak coherency in response at an intermediate noise level. The coherency is quantified by the signal-to-noise ratio, correlation time, and inter-spike intervals for conclusive evidence of the phenomenon. The effects of the findings could be far-reaching in aeroelasticity: noise could be used constructively to excite the desired coherent responses to increase the energy harvested from the structure, or conversely, trigger flutter instability which is detrimental to the structure.