Dynamic behavior and energy harvesting potential of a circular cylinder experiencing flow-induced motions in elevated turbulent inflow

Understanding flow-body interactions under oscillation is crucial for enhancing energy harvesting or maintaining structural stability. Elevated levels of inflow turbulence further complicate the problem, as they can potentially affect the dynamic behavior of structures; however, their specific impacts on energy harvesting mechanisms and oscillation patterns remain underexplored. In this experimental study, flow-induced motions under elevated turbulent inflow conditions are examined using an active grid turbulence generator that creates turbulence intensities of 13.4 % and 19.4 % in a range of Reynolds numbers between 1800 and 32000. Plain and surface-modified cylinders were examined for their oscillation behaviors in the transverse direction. It was observed that turbulence leads to oscillation suppression at most inflow velocities. Moreover, at the onset of the VIV upper branch, a slight decrease in power by ∼25 % is observed for the turbulent inflow cases compared to the laminar baseline. For a surface-modified cylinder (H/D = 1.6 %), turbulence enhances the mechanical power output as the system hits galloping compared to the laminar case, which transitions to the lower branch. An increase of up to 190 % of mechanical power output is observed. However, as the surface thickness increases (H/D = 3.2 % or higher), mechanical power output under elevated inflow turbulence is up to 40 % lower. A higher coefficient of variation of mechanical power under turbulent inflow conditions indicates decreased oscillation stability.