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Energy converters based on vortex-induced vibrations (VIV) have shown great potential for harvesting energy from low-velocity flows, which constitute a significant portion of ocean energy. However, solid-solid triboelectric nanogenerators (TENG) are not wear-resistant in corrosive environments. Therefore, to effectively harvest ocean energy over the long term, a novel solid-liquid triboelectric nanogenerator based on vortex-induced resonance (VIV-SL-TENG) is presented. The energy is harvested through the resonance between VIV of a cylinder and the relative motions of solid-liquid friction pairs inside the cylinder. The factors that affect the output performance of the system, including the liquid mass ratio and the deflection angle of the friction plates, are studied and optimized by establishing mathematical models and conducting computational fluid dynamics simulations. Furthermore, an experimental platform for the VIV-SL-TENG system is constructed to test and validate the performance of the harvester under different conditions. The experiments demonstrate that the energy harvester can successfully convert VIV energy into electrical energy and reach maximum output voltage in the resonance state. As a new type of energy harvester, the presented design shows a promising potential in the field of 'blue energy' harvesting. [ABSTRACT FROM AUTHOR]

In this study, two thin rectangular PVDFs were installed in the form of a cantilever on a FTEH (funnel-type energy harvester), and a CTEH (cymbal-type energy harvester) was fabricated in a form coupled to the upper part of the support. As a result of measuring the energy harvesting sensitivity according to the installation direction of the CTEH, a high voltage was measured in the structure installed on top of the support across all flow velocity conditions. A composite structure PVDF energy harvester combining CTEH and FTEH was fabricated and the amount of power generated was measured. As a result of measuring the open-circuit voltage of the PVDF energy harvester device with a composite structure to which the optimum resistance of CTEH of 241 kΩ and the optimum resistance of FTEH of 1474 kΩ were applied at a flow rate of 0.25 m/s, the output voltage compared to the RMS average value was 7 to 8.5 times higher for FTEH than for CTEH. When the flow rate was 0.5 m/s, the electrical energy charged for 500 s was measured as 2.0 μWs to 2.5 μWs, and when the flow speed was 0.75 m/s, it reached 2.5 μWs when charged for 300 s, generating the same amount when the flow rate increased by 50%. The time to do it was reduced by 66.7%. [ABSTRACT FROM AUTHOR]

With growing innovations on the Internet of Things capabilities, automated monitoring and remote sensing applications have become important in the modern world. However, with thousands of distributed sensors and wireless communication routers, the power supply continues to be one of the main challenges for an efficient and sustainable operation. This paper deals with designing, developing, and testing a nonlinear airfoil-shaped piezoelectric energy harvester from flow-induced vibration. The harvester converts flow-induced vibration from water into electrical energy that can be conveniently stored and used to power smart remote sensors. A passive self-adjustable base compensates for the changing flow direction that can reduce the conversion efficiency of energy harvesters. Different beam substrate profiles were investigated for misalignment correction with thin airfoil profiles able to orient faster at higher misalignment angles. The airfoil-shaped piezoelectric energy harvester outperformed the conventional rectangular beams with equal volume with an additional inline mode observed for the same frequency range in low-velocity flow. The piezoelectric macro-fiber composite had an average RMS output of 132 mV for transverse oscillations in the absence of flow misalignment. Experimental studies have shown a performance reduction in both time and frequency domains between 50% and 60% for flow misalignment reaching up to 30°. • An airfoil-shaped piezoelectric energy harvester with a rotating base for pipeline applications was proposed. • A self-aligning property can compensate for flow changes in open or closed boundary conditions. • Analytical, computitational and experimental optimization of vortex-induced vibration in water utilizing synchronization and added mass modelling. • Experimental and computational data highlighting energy conversion efficiency reduction for misaligned flows. [ABSTRACT FROM AUTHOR]