Controlled Transverse Oscillation of a Parallel Linkage-Airfoil Mechanism for Enhanced Vortex-Induced Energy Harvesting

Harnessing energy from low-velocity fluid flows via vortex-induced vibrations (VIV) presents a significant challenge, primarily due to the chaotic and multi directional nature of the resulting structural oscillations. This study introduces and validates a novel energy harvesting mechanism designed to overcome this limitation by controlling the vibrational response of an oscillating body. The mechanism consists of a parallel linkage coupled with an airfoil, strategically placed in the wake of a circular cylinder to constrain the airfoil's chaotic motion into a predictable, high-amplitude transverse oscillation. A combined experimental and numerical approach was employed for design validation. Experimental tests were conducted in an open flow channel at a steady velocity of 0.15 m/s. A NACA0015 airfoil, coupled to the parallel linkage mechanism, was positioned downstream of a 60 mm diameter cylinder. The airfoil's transverse displacement was captured using high-speed videography. Concurrently, a three-dimensional (3D) Fluid-Structure Interaction (FSI) simulation was performed using the Spalart–Allmaras turbulence model, precisely replicating the experimental geometry and flow conditions. The results reveal a good correlation between the experimental and 3D numerical results. Crucially, the parallel linkage mechanism successfully constrained the airfoil's motion to a purely transverse direction, with both methods showing consistent oscillation frequencies and comparable displacement amplitudes. This successful validation of the 3D numerical model against experimental data not only confirms the mechanism's effectiveness but also establishes a robust foundation for the extensive, simulation-driven parametric studies required for system optimization.