# Design and Development of Bladeless Vibration-Based Piezoelectric Energy-Harvesting Wind Turbine
## 1 Introduction  
In recent years, there has been a spike in interest in exploring various environmentally friendly and renewable energy-harvesting designs that can address global energy and environmental concerns. The use of wind energy and the delivery of power for electronic devices via aeroelastic vibration has been studied. Some researchers have focused on collecting aeroelastic energy from aerofoils, while others have concentrated on converting energy created by vortex-induced vibrations (VIV). VIV is an energy harvesting method that uses the vortex shedding phenomena, in which an oscillating lift force is applied to a body, and the interaction between the fluid and the solid structure, which in practice is an elastic structure, allows engineers to generate electricity [1]. The VIV of a structure is often related to various engineering problems. For example, VIV can cause vibrations in heat exchanger tubes and change the dynamics of riser tubes that convey oil from the seabedto the surface. VIV also has ramifications for marine and land vehicle design and causes large-amplitude vibrations in anchored structures in the ocean. On the positive side, a long cylinder mounted on a flexible structure can be used to gather energy created by VIV. The cylinder is susceptible to vortices that regularly shed, causing transverse vibrations. The vibrations can then be transformed into electric power using piezoelectric generators mounted on the cylinder. Most VIV harvesters have a narrow output band around wind speed, where the structure's inherent frequency equals the vortex shedding frequency. The presence of real-world scenarios such as the vibrations of offshore structures and riser pipes, building vibrations, and fluid movement in a heat exchanger, among others, has generated interest in studying VIV. VIV was initially thought to have harmful effects. The viscous effects of a fluid flowing over a cylindrical body, for example, separate it from the surface. When the liquid separates from the surface, new forces emerge on the surface, which are large enough to cause the structures to vibrate, triggering them to break. A thorough understanding of the nature of VIV from a design standpoint is required to use these vibrations to create energy and avoid technical failures. While aeroelastic resonance is considered a nuisance, it provides the technological underpinning of wind energy conversion. Over the last two decades, several researchers have investigated the problem of harvesting energy from flow-induced vibrations [2; 3]. In an experimental context, [PERSON] et al. [4] examined a bio-inspired leaf architecture that transfers wind energy into usable electric power. In addition, energy harvesting devices were proposed by [PERSON] et al. [5] and [PERSON] [6] employing piezoelectric and electromagnetic transduction technologies with vibrations produced by wake galloping. Lock-in or synchronization of VIV happens when one of the inherent frequencies of the dynamic design equals the frequency of vortex shedding, resulting in vortex-induced vibrations (VIVs). Through experiments, [PERSON] et al. [7] employed flexible piezoelectric material under VIV for energy gathering. [PERSON] et al. [8] investigated energy harvesting from circular cylinder VIV. [PERSON] et al. [5] investigated the effects of Reynolds number and electrical load resistance on the lock-in zone as well as the performance of the energy harvester. Finally, [PERSON] et al. [9] conducted another experiment in which the energy harvester's output performance was investigated by altering the flow speed and testing the self-excited energy harvester subjected to uniform cross flows. Based on the experimental work of [PERSON] et al. [9], [PERSON] et al. [10] developed a theoretical distributed-parameter model and used the Euler-Lagrange method to achieve reasonable agreement with the experimental results. Another comparison study was undertaken by [PERSON] et al.