Piezoelectric Harvesters for Flow-Induced Vibration Energy: Recent Advances, Challenges, and Prospects

Energy harvesting from flow-induced vibrations (FIVs) is one of the cleanest methods for powering miniature devices, such as wireless sensor network (WSN) devices and medical appliances. Due to the simplicity and effectiveness of piezoelectric devices, FIV-based piezoelectric energy harvesters (FIVPEHs) have caught the attention of researchers in recent years. Unlike previous narrative studies, this work presents a normalized, cross-mechanism comparison of FIVPEHs using volumetric power density, cut-in velocity, and bandwidth as unified metrics to reveal quantifiable performance trade-offs among vortex-induced vibration (VIV)-, wake-induced vibration (WIV)-, galloping-, and flutter-based harvesters. This study begins by discussing the fundamental concepts of piezoelectric effects, classifying the FIVPEHs. It then investigates and compares different approaches for enhancing conventional FIVPEH performance, utilizing normalized performance metrics, such as volumetric power density, cut-in velocity, and operational bandwidth. The comparative investigation reveals distinct scenarios; for example, WIV systems achieve the highest reported power density, reaching 1024.242 mW/cm³ under optimal wake interference conditions. VIV harvesters demonstrate an extremely low cut-in velocity (as low as 0.01 m/s), well-suited for hydrokinetic applications. Galloping-based harvesters offer a balanced performance, achieving power densities of up to 4.918 mW/cm³, while flutter-based harvesters can generate higher energy densities of up to 15.73 mW/cm³, albeit typically requiring higher flow velocities. Finally, this study outlines the major challenges hindering the commercialization of FIVPEHs and proposes future research directions to address these limitations. The primary limitation of the current FIVPEHs is the lack of a comprehensive evaluation of their performance indicators, which restricts their widespread use. Hence, a proper evaluation strategy is needed through the implementation of cutting-edge research in the relevant field. This paper serves as a guide for researchers seeking to enhance performance and broaden the application of FIVPEHs, offering insights to direct future research efforts.