This paper presents energy harvesting results by applying vortex-induced vibration (VIV) and galloping excited with a circular cylinder and a triangular cylinder, respectively in a low-speed water flume. The voltage and power were obtained by the energy harvesters under different resistances (0-∞) and flow velocities (0.05~0.35m/s). The results demonstrate that for the VIV harvester, when the flow velocity increases, the voltage and power of the cylindrical cantilever beam increase initially, then decrease. The harvested maximum power density is 97.09μW/cm3 at the flow velocity of 0.16m/s. For the galloping harvester, the voltage and power of the triangular cylinder cantilever beam increase with the increase of flow velocity. The harvested maximum power density is 502.04μW/cm3 at the flow velocity of 0.35m/s. The triangular cylindrical cantilever beam has better performance in energy collection efficiency because of applying the galloping response of structure.
Due to the decreasing of non-renewable energy and the harm of fuel cell to environment, more and more researchers pay attention to the development and utilization of renewable energy. At present, more mature power generation methods mainly by applying solar energy, tidal energy, wind energy, etc, are proposed for the power supply of high-power electrical devices. However, with the development of miniaturized sensor networks, micro-electromechanical systems (MEMS) and Internet of Things to use the inexhaustible energy in the surrounding environment, piezoelectric materials have gradually become a research hotspot (Azizi et al., 2016; Mohanty et al. 2019). Pillatsch et al.(2016). The power density of piezoelectric materials in the micro energy capture system is much higher than that of other energy collection methods and is better in economy (Bernitsas et al., 2008; Cook-Chennault et al., 2008) and some research achievements have been made.
At present, main energy source of piezoelectric energy acquisition device is flow-induced vibration, including VIV, galloping and flutter. Bernitsas et al. (2008) gave out that the characteristics of VIV power generation devices as energy collection, are of high energy density, low maintenance costs, and a life cycle of 10-20 years. The vortex induced vibration aquatic clean energy (VIVACE) converter was first proposed and applied for a patent. Lan et al. (2019) conducted dynamic modeling of VIV energy collection. Wang et al. (2020a) modeled and simulated the vortex induced vibration generator to improve the vortex induced vibration of the cylinder, and applied an additional rod to improve the power output. Zhou and Wang (2018) proposed the application of double series cylinders to improve VIV power generation. Qin et al. (2019), Sun et al. (2019) respectively carried out the researches on VIV piezoelectric energy devices.
