Numerical investigation on energy extraction efficiency of an elastically mounted downstream rigid cylinder in tandem arrangement when upstream cylinder is fixed

The energy extraction efficiency from vortex-induced vibrations (VIV) for a single cylinder and a downstream cylinder in the tandem arrangement was investigated over a range of reduced velocities for different mass-damping parameters (m*ζ = 0.184, 0.288, 0.407 and 0.719) using the wake oscillator model (WOM). The present study introduced an empirical parameter η in WOM to replicate the experimental response of the Elastically Mounted Rigid Cylinder (EMRC) at the downstream in tandem configuration. The energy efficiency of each m*ζ is investigated for both isolated single-cylinder and downstream cylinder in the tandem arrangement at six different spacing ratios. The optimum spacing ratio of L/D = 4 consistently showed the best outcome in tandem arrangement, suggesting that optimal tuning of inter-cylinder spacing has the ability to maximize wake-induced energy transfer. Renewable energy harvesting in real systems can be performed effectively using strategically configured tandem cylinder systems, particularly where flow conditions vary or structural damping is high.