Performance-enhanced piezoelectric energy harvesting system induced by Karman vortex using concave pseudo-blunt body structure

Abstract Piezoelectric energy harvesting is one of the important technologies for environmental monitoring sensors to realize self-power supply. In recent years, the technology of fluid-induced piezoelectric vibration energy harvesting for blunt body structures based on Karman vortex street effect has been widely studied. In order to further improve the efficiency of energy harvesting, a performance-enhanced method of Karman vortex street energy harvesting based on structural modification is proposed. Different pseudo-blunt bodies with concave surfaces are designed and combined with piezoelectric device to harvest energy. The finite element simulation results show that, compared with the cylindrical blunt body, the pseudo-blunt body with concave surface can enhance the turbulent action of the fluid and make the Karman vortex shedding more intense. Especially for the pseudo-blunt body with S -concave, the amplitude of Karman vortex street and the turbulent kinetic energy behind the pseudo-blunt is strongest. In addition, based on wind tunnel, the energy harvesting performance of Karman vortex behind a cylinder with different surface structures is experimentally studied. The experimental results show that the piezoelectric energy harvesting efficiency behind the cylindrical pseudo-blunt body with concave surface is better than that behind the cylindrical blunt body without concave surface. In particular, the S -concave pseudo-passivate has the best energy harvesting performance, with a peak output voltage of 23.6 V, an output voltage span of 31.2 V, a maximum current of up to 0.23 mA, and a maximum power density of up to 6.64 W m −3 , which are 136% and 81% higher than that of the ordinary cylindrical passivate, with an increase in the maximum current of 155% and an increase in the optimal power density of 532%, respectively. The above results show that the concave-based pseudo-blunt body structure can effectively improve the efficiency of vortex energy harvesting using piezoelectric mechanism, which lays an important foundation for the development and application of piezoelectric vortex energy harvesting theory.