Average power output and the power law: Identifying trends in the behavior of fluidic energy harvesters in grid turbulence

While the majority of the literature in energy harvesting is dedicated to resonant harvesters, non-resonant harvesters, especially those that use turbulence-induced vibration to generate energy, have not been studied in as much detail primarily due to their comparatively small power output, general non-tunability and difficulty in associating flow conditions to harvester behavior. In this extensive study, we look at the behavior of piezoelectric cantilever beams in different types of grid turbulence with the intention of identifying trends in the harvester output. Our results show that the power-law decay of the harvester output that had previously been observed for rectangular grids holds for a wide variety of fractal grids as well. Additionally, experimental data shows that the average harvester output in grid turbulence follows a power-law growth with respect to the mean flow velocity for relative short and stiff piezoelectric beams.