Numerical simulations of aeroelastic instabilities to optimize the performance of flutter-based electromagnetic energy harvesters

The article presents a two-dimensional fully coupled fluid-structure interaction model for simulating aeroelastic instabilities to evaluate and optimize the performance of flutter-based electromagnetic energy harvesters. The flutter-type unstable vibration of T-shaped cantilever systems is investigated as a driving mechanism for small-scale energy conversion. A flow solver based on the vortex particle method and a structural solver based on a corotational finite element formulation are coupled in order to accurately account for the geometrically nonlinear effects of such very flexible elements. A reference harvester is simulated considering the damping effects arising from the electromagnetic transducer. The estimated flutter wind speed and the predicted energy outputs under different electrical resistances are found to agree reasonably well with reference wind tunnel experiments. The influence of physical parameters such as length, thickness, and cantilever tip height on the performance of the harvester is investigated up to an envelope volume of 42cm(3). The maximum power output is found to be 5.3mW at 8m/s. The optimized harvester shows a better performance under low wind speeds by producing 0.65mW at 4m/s where the reference harvester produced no power.