Effect of Incidence Angle on the Performance of a Dual Cantilever Flutter Energy Harvester

This paper analyses the effect of incidence angle on the performance of a dual cantilever flutter (DCF) energy harvester. An experiment was conducted for incidence angles of 0°, 30°, 60° and 90° about the z-axis where the 0° angle correspond to the case where both cantilever beams are positioned perpendicular to the wind flow. The electromagnetic power output was then theoretically estimated from the experimental measurements. Results demonstrate that from 0° to 60°, the critical flutter speed of the device decrease with angle of incidence, which highlights a potentially larger bandwidth. However, the flutter amplitude also decreases with incident angle, recording a 54.7% decrease at 60° when compared with 0°. This corresponded to a 76.1% drop in predicted power output. At 90°, flutter was not recorded within the tested wind speeds. The experiment was then repeated by rotating the DCF 90° about the x-axis. The results obtained this time was very similar to the 0° angle along the z-axis in terms of amplitude and power. However, the critical flutter speed was reduced by 16.3%. Interestingly, the flutter frequency remains approximately constant after the critical flutter speed for all tested incidence angle. Finally, some important considerations to maximize the performance for the device were provided.