A First Look at Side-by-Side Piezoelectric Harvesters in Fractal Square Grid-Generated Turbulence

While the vast 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. This is especially true for grid-generated turbulence. In this study, the interaction of two side-by-side fluidic harvesters from a passive fractal square grid-generated turbulent flow is considered. The fractal grid has been shown to significantly increase the turbulence generated in the flow which is the source of the vibration of the piezoelectric beams. In this experimental study, the influence of four parameters have been investigated: (i) Beam lengths and configurations, (ii) Mean flow velocity, (iii) Distance from the grid and (iv) Gap between two beams. Experimental results show that the power output per beam from the fractal square grid is at worst similar to the output from a classical grid with a much larger blockage ratio.