Stochastic stability of an aeroelastic harvester contaminated by wind turbulence and uncertain aeroelastic loads

Abstract

The study describes the extension of a recently developed model that examines the stochastic stability of a torsional-flutter-based harvester. The new, extended model accounts for both uncertainty in the aeroelastic loads and wind turbulence effects. The first uncertainty source is a byproduct of the modelling simplifications of the aeroelastic loads, which are described by indicial function approach and ideally applicable to two-dimensional flow. The second source is the flow turbulence that operates by modifying the load through parametric, stochastic perturbations that are applied to the term describing the memory-effect of the load; stochastic perturbations simulate imperfections in the load assessment (e.g., measurement errors). Furthermore, since the “blade-airfoil” used for energy harvesting has finite dimensions, three-dimensional flow effect is simulated through a load reduction parameter applied to the static lift slope, dependent on the aspect ratio of the apparatus; this reduction parameter also leads to approximations and stochastic perturbations. Mean square stochastic flutter stability is examined. Post-critical states are discussed.