Finite element modeling of fluid-solid-piezoelectric for investigating the ways of improving the performance of the micro energy harvester in the fluid flow

In this paper, a coupled fluid-solid-piezoelectric model has been developed by the finite element method to study and improve the performance of a micro piezoelectric transducer designed for fluid flow energy harvesting. In the studied harvester, when the turbulence flow of water passes over a bluff body, the vortex shedding phenomenon occurs periodically and applies a periodical lift force to a piezoelectric beam placed in the downstream region. The resulting oscillations in the piezoelectric beam lead to electrical power generation. Navier-Stokes equations and large-eddy simulation method have been used to describe the fluid turbulence flow, and equations of conservation of linear momentum along with piezoelectric constitutive relations in strain-charge form have been employed to obtain the solid deformation and the electric field intensity. Numerical experiments designed by Taguchi’s method have been used to study the effect of different parameters on the harvester performance. The results of these experiments have shown that using a triangular or D-shape bluff body, and selecting the minimum possible values for the length to height ratio of the bluff body, the distance between the beam and the bluff body, and eccentricity of the beam relative to the bluff body is beneficial for better performance of the harvester. Furthermore, the shape of the bluff body has been the most influential parameter on the harvester performance in this study.