Passively enhanced VIV responses of side-by-side cylinders at moderate Reynolds number

Abstract

Stationary upstream cylinders were used to enhance the response of vortex-induced vibration (VIV) of side-by-side (SBS) cylinders at Reynolds number Re = 1000. A modified direct-forcing immersed boundary (DFIB) with a large eddy simulation (LES) technique was employed to get the numerical solution. The VIV responses and VIVACE (vortex-induced vibration for aquatic clean energy) efficiency were investigated for various reduced velocities (UR∗) at a constant mass-damping (m∗ζ). Furthermore, the influence of diameter (d∗) and spacing (s∗) of stationary upstream cylinders on the enhancement of amplitude response and VIVACE efficiency were analysed. The optimal upstream cylinder diameter and spacing were d∗ = 0.4 - 0.6 and s∗⩽ 0.4. Within these ranges, the enhancement of amplitude response and efficiency was observed for UR∗⩾ 5.0, while the decrease in amplitude response and efficiency for UR∗ = 4.0 – 4.5 was minimized.