Flow-induced vibrations of various bluff bodies: a review of blockage and wall effects

Bluff bodies subjected to fluid flow are unconfined or confined by two parallel walls or by one wall in many engineering applications and nature. They may undergo vortex-induced vibration (VIV) and/or galloping depending on the body shape and the confinement degree. This paper presents a review of flow-induced vibrations of confined bluff bodies of different cross-sections, including circular, square, rounded-corner, and rectangular. Synthesized are the effects of the flow confinement by two walls (two-wall–cylinder interactions) or one wall (one-wall–cylinder interactions) on vibration response, frequency response, lock-in, aerodynamic force, vortex shedding, motion trajectory, phase lag, VIV width, hysteresis in VIV, and galloping at different ranges of mass ratio, damping ratio, and Reynolds number. For a circular cylinder, an increase in blockage ratio reduces the maximum vibration amplitude, causes a shrink in the VIV width and a shift in the VIV regime to smaller reduced velocities, and introduces hysteresis between initial and lower branches. For a square cylinder, the effect of blockage ratio on vibration amplitude is not straightforward but depends on the cylinder mass ratio. A higher blockage ratio suppresses galloping for a square cylinder. The research gap in the literature is pinpointed and put forward for future investigations.