Power Generation from Airflow Induced Vibrations

Abstract

This paper presents a coupled mechanical device that generates power by a direct conversion of the air flow into mechanical vibrations. The mechanism experiences a fluid force that changes with its orientation causing vibrations. The device consists of two tightly coupled parts: a mechanical resonator that produces high-frequency mechanical oscillations from quasi-steady airflow resulting in large amplitude vibrations and a piezoelectric power generator harvesting the energy from the resonator's motion. Assuming that the fluid-structure interactions solely depend on the instantaneous velocity, these interactions were studied using numerical modeling and wind-tunnel tests. The proposed energy harvester allows for locking up the device's lowest natural frequency to the vortex-shedding resonant frequency induced by the ambient energy source. The energy harvester demonstrated a peak-to-peak output voltage of 25V at 10Hz, from an input wind velocity of ∼7 m/s.