Numerical Study of the Aerodynamic Response and Energy Harvesting of Polyvinylidene Fluoride Piezoelectric Flags in a Uniform Flow

The kinetic energy of airflow is renewable and exists everywhere. It can drive the piezoelectric energy harvester to vibrate, which can convert energy of airflow into electricity. This paper presents the constructive vibration modes of multi-piezoelectric flags (MPF) for energy harvesting in a uniform flow. The aerodynamic response and energy harvesting of both the single piezoelectric flag (SPF) and the MPF are investigated by a 2D-numerical method. This method is fully coupled fluid-structure-electric (FSE) by using the immersed boundary-lattice Boltzmann method, Euler-Bernoulli beam and the piezoelectric theory. As an application, the dynamic characteristics of the SPF at a stable state are described. As for the MPF, vortices shedding from the piezoelectric flag effect the vibration of surrounding flags. In-phase vibration modes of the MPF, as the constructive vibration modes for the energy harvesting, can be obtained in tandem and side-by-side patterns. The vibration characteristics of the MPF are effected by the streamwise and spanwise gap distances. Multi-times electrical energy can be achieved using the MPF compared with the SPF alone in a uniform flow.