Energy Harvesting for Sensors using Free-Floating Flaps : Wind Tunnel Experiments

In this paper, a novel configuration of an energy harvester for local sensing using limit cycle oscillations has been designed, modeled and tested. A wing section has been designed with two free-floating flaps (FFF). The FFF are aerodynamically balanced flaps that are free to rotate around their rotation axis and are only controlled by trailing edge tabs. In the rotational axis of each flap a dynamo is mounted that converts the vibrational energy into electricity. It has been demonstrated numerically how a simple electronic system can be used to keep such a system at stable limit cycle oscillation by varying the resistance of the electric circuit. The system has been manufactured and tested in the Open Jet Wind Tunnel Facility of Technical University Delft. The numerical results could be reproduced and voltage generation could be demonstrated at cost of a moderate decrease in lift of 2%.