Suppression of vortex-induced vibrations of a cylinder in inertial-elastic flow

Abstract

We study Vortex-Induced Vibration (VIV) of a one-degree-of-freedom cylinder placed in inertial-elastic flows experimentally. We show that there is a critical Reynolds number for the onset of VIV in these flows and this critical Reynolds number increases when the elasticity in the fluid is increased. We also show that at a constant Reynolds number, adding elasticity to the fluid reduces the amplitude of oscillations and eventually suppresses VIV entirely. For the cases where VIV is observed, the onset of the lock-in range does not depend on the Reynolds number, as a result of the competing effects of shear-thinning and elasticity. The vortices that are observed in the wake are significantly different from those observed in Newtonian VIV: the vortices are S-shaped with relatively long tails that influence the formation of the vortices that are formed in the following cycle.