A hybrid piezoelectric-electromagnetic wind energy harvester: influence of undisturbed vorticity formation on performance

The performance of a hybrid piezoelectric-electromagnetic-based wind energy harvester (HPEWEH) is presented in this article. Wind flow over a bluff body produces vortex-induced vibration (VIV), which is harvested simultaneously via a piezoelectric patch and an electromagnet. The orientation of HPEWEH is crucial for directing undisturbed wind flow and vortex formation. The hybrid piezoelectric-electromagnetic harvester integrates two electromechanical transduction systems: a piezoelectric macro-fiber composite and an electromagnetic mechanism. These systems are coupled via a bluff body, which is excited by vortex-induced vibrations (VIV), enabling simultaneous energy conversion from mechanical oscillations. The piezoelectric composite is bonded to a substrate beam to convert the mechanical strain into electricity. Additionally, electricity is produced in the electromagnetic section by converting changes into magnetic flux inside a container made from two slits that are wrapped with coils. A simulation study is conducted using ANSYS Fluent to investigate turbulence in the two configurations. In Configuration A, the bluff body faces the incoming wind, with the beam positioned behind it in the wake region. Conversely, Configuration B has the beam at the front, followed by the bluff body in the wake region. It is found that configuration B allows for the undisturbed production of vortices, resulting in a 33% greater gain in turbulent energy. Moreover, a larger output voltage is produced during frequency synchronization because, under synchronization, the vortex-shedding frequency and the structure's natural frequency are the same. The maximum voltage output occurs in this region, with configuration B producing 15% more voltage output than configuration A.