Nonlinear dynamics and performance enhancement of a flow energy harvester with time-delayed modulation

Abstract

This study investigates a nonlinear vibration-based energy harvesting (EH) system consisting of a galloping-induced oscillator coupled to an electrical circuit through piezoelectric transduction. The mechanical subsystem incorporates time-delayed feedback whose amplitude is periodically modulated at a frequency close to twice the natural frequency of the structure. Using the method of multiple scales, approximate analytical expressions are derived for the steady-state oscillation amplitude and the corresponding harvested electrical power. The results demonstrate that the proposed delay modulation mechanism can significantly enhance vibration amplitudes and EH efficiency within a specific range of wind velocities. This improvement is attributed to a delay-induced parametric resonance effect that amplifies the system response. The analytical predictions are validated through numerical simulations, showing excellent agreement between both approaches.