Analysis of galloping competition characteristics and energy harvesting capacity of TGPEH based on stiffness ratio design

In this paper, an innovative strategy is presented to improve the energy harvesting performance of a tandem galloping piezoelectric energy harvester (TGPEH) by optimizing the stiffness ratio of two bluff bodies. To precisely characterize the fluid force around the bluff bodies, a finite element model based on Reynolds-Averaged Navier–Stokes (RANS) equations is established. Combined with the Fourth-order Runge-Kutta method, a time-domain systematic approach for synchronously solving the complex aero-electro-mechanical coupling of the TGPEH is set up. The simulation results exhibit excellent agreement with the experimental data, thereby validating its predictive accuracy. On this basis, influences of stiffness ratio on galloping competition characteristics and the energy harvesting performance of the TGPEH are studied in detail under Reynolds numbers (Re = 4000–16000) and spacing (L = 2∼8D). The results reveal that an optimized stiffness ratio (η = 2.04) achieves a remarkable 175.9 % increase in output power compared to that at η = 1. Additionally, the output power and energy conversion efficiency of the TGPEH can both achieve high performance simultaneously by designing the stiffness ratio. These findings offer a novel design paradigm for high-performance TGPEHs and provide a robust methodology to the field of flow-induced energy harvesting.