Harvesting Energy from Galloping Oscillations

The aim of this work is to exploit flow-induced vibration for energy harvesting. A cantilever beam carrying a tip mass in the form of a lightweight box having a square, triangular, or semicircular cross-section is designed to undergo galloping oscillations when subjected to an incoming wind stream. Electrical power is extracted from the self-excited flexural vibration of the beam through an electromagnetic generator consisting of a permanent magnet that is attached to the beam oscillating past a stationary coil. A theoretical model is developed to predict the system dynamics in terms of its design parameters. Emphasis is placed on developing finite element models to assess the lift and drag coefficients, together with their variation with the angle of attack, which are known to affect the aero-elastic behavior significantly. The resulting predictions of the lift and drag forces are then implemented in an electro-aeroelastic model to predict the output voltage and power. The results are supported by experimental measurements over a range of load resistance.