Aeroelastic flutter energy harvester design: the sensitivity of the driving instability to system parameters

Abstract

This study examines the design parameters affecting the stability characteristics of a novel fluid flow energy harvesting device powered by aeroelastic flutter vibrations. The energy harvester makes use of a modal convergence flutter instability to generate limit cycle bending oscillations of a cantilevered piezoelectric beam with a small flap connected to its free end by a revolute joint. The critical flow speed at which destabilizing aerodynamic effects cause self-excited vibrations of the structure to emerge is essential to the design of the energy harvester because it sets the lower bound on the operating wind speed and frequency range of the system. A linearized analytic model of the device that accounts for the three-way coupling between the structural, unsteady aerodynamic, and electrical aspects of the system is used to examine tuning several design parameters while the size of the system is held fixed. The effects on the aeroelastic system dynamics and relative sensitivity of the flutter stability boundary are presented and discussed. A wind tunnel experiment is performed to validate the model predictions for the most significant system parameters.

Aeroelastic energy harvesting: A review

“…Other linear analyses were performed by Bryant and his coauthors (Bryant & Garcia, 2011;Bryant, Wolff, & Garcia, 2011). The authors presented theoretically and experimentally a guideline to design piezoaeroelastic energy harvesters that can generate energy at low freestream velocities.…”

Energy harvesting by means of flow-induced vibrations on aerospace vehicles

“…The equations of motion of the EH system were used to calculate the linear flutter speed and the effects of flow velocity on flutter frequency and power output [58]. Methods for expanding the operating envelope of the power harvester and reducing the linear flutter speed were proposed [34,117,118].…”

Optimisation of an Aeroelastic Flutter Energy Harvester

“…There has been much investigation into optimising the system parameters to minimise the critical flutter speed as to optimise the range of flow speed the energy harvester can operate within. 10 As well as improving the the range of operational flow speeds, it is also desirable to enhance the system to maximise the power output. This type of energy harvester currently doesn't generate much power, milliwatts are produced intended to power small sensor systems rather than contribute to the grid.…”