Performance enhancement of hydrodynamic piezoelectric energy harvester by array disturbance

Utilizing piezoelectric transduction to harvest low-velocity water flow energy to power wireless devices has become a promising alternative to battery power supply. This paper proposes to incorporate disturbance columns in the water flow to improve the energy harvesting performance of piezoelectric energy harvester. Using a modified Van der Pol model and a quasi-steady hypothesis to determine the vortex-induced vibration and galloping force, respectively. Piecewise distributed parameter model of vortex-induced vibration and galloping considering the array disturbance are presented, and the approximate analytical solution of the models are derived. Experimental studies are conducted, and it showed that the disturbance columns had a significant modulating effect on the output power of the harvester. The completely arranged disturbance columns stabilized the water flow and suppressed the vibration of the bluff body. Removing the disturbance columns in front of the bluff body gradually can increase the local flow velocity and improve the power of the harvester. At the flow velocity of 0.5 m/s, the power densities of semi-cylinder and cylinder harvesters both reach the maximum under working conditions II-10, reaching 3.98 kW/m3 and 0.41 kW/m3, which are 144.6 times and 5.4 times higher than those without the array disturbance columns, respectively. The theoretical model results are in good agreement with the experimental results. Three-dimensional transient numerical simulations are introduced to analyze the flow field characteristics after the addition of the array disturbance columns, and the experimental results and theoretical model results are verified. •Modeling the piezoelectric energy harvester after considering array disturbances.•The analytical models are validated by the circulating water channel experiments.•Array disturbance columns are introduced to change the flow field.•Venturi effect is the reason of performance enhancement.•Disturbance increases the harvested power by up to 144.6 times.