Power Evaluation for Flutter-based Electromagnetic Energy Harvester Using Cfd Simulations

Structural instability caused by self exciting aerodynamic forces (flutter) can be used as an effective input source for small scale energy harvesters. The self exciting aerodynamic force exerted on a T-shape cantilever causes periodic vibration, which can be converted into electric power through an electromagnetic transducer. Due to the complexities inherent in the fluid-structure interaction between the cantilever harvester and wind flow, analyzing the structural response of the cantilever and estimating the power output from the flutter based energy harvester is challenging. Here, a CFD code based on the Vortex Particle Method is employed to simulate the wind induced responses of a T-shape cantilever beam and to estimate the power output extracted from the flutter vibration. The estimated aerodynamic damping parameter, together with the mechanical and electrical damping parameters in the harvester are then used to find the critical wind speed of flutter onset as well as the optimum load resistance. Results are supported by wind tunnel tests conducted.