Influence of upstream staggered cylinder on vortex-induced vibration responses of side-by-side cylinders in turbulent flow

A direct-forcing immersed boundary method with large-eddy simulation was used to simulate the phenomenon of the vortex-induced vibration (VIV) of multiple cylinders in a flow field. The present study analyzed the influence of an upstream stationary cylinder on the vibration behavior of two side-by-side cylinders downstream in a staggered position. The latter two side-by-side cylinders were allowed to vibrate in the cross-flow direction. By using different center-to-center distances between cylinders, damping ratios, mass ratios, Reynolds numbers, and diameters of the upstream stationary cylinder, the VIV response and energy conversion efficiency of the vibrating cylinders were studied. The results showed that the amplitude and efficiency of the vibrating cylinders are significantly enhanced at reduced velocity UR*≥6.0 when compared with a single vibrating cylinder. The maximum values of amplitude and efficiency can be shifted and enhanced, respectively, by adjusting the mass ratio and damping ratio. Reducing the diameter of the stationary upstream cylinder can effectively improve efficiency, especially in the lock-in region.