SUPPRESSING VORTEX-INDUCED VIBRATIONS VIA PASSIVE MEANS

We investigate the hydrodynamic effect of a slit in a circular cylinder. The goal of this study is to find a modification of a cylinder to minimize vortex-induced vibrations (VIV). The slit, which is parallel to the incoming flow, is found to be very effective in suppressing vortex shedding and consequently VIV. Through a series of numerical experiments, the optimal size of the slit to suppress the lift force and VIV is obtained. We also find that the slit is more effective at higher Reynolds numbers. A linear stability analysis shows that jet flow though a slit changes the stability behind the cylinder by inducing two small pockets of absolute instability followed by bands of convectively and absolutely unstable regions.