Three distinct response regimes for the transverse Vortex-Induced Vibrations of circular cylinders at low Reynolds numbers

Abstract The paper reports and discusses the results of a numerical investigation of the low-Reynolds-number transverse Vortex-Induced Vibrations (VIV) of low-mass-ratio elastically supported circular cylinders. Simulations were conducted over a large range of reduced velocities, from 2.5 to 20.0 , at Reynolds numbers from 50 to 400. The objective of the study was to ascertain the dependency of the transverse vibrational behaviour of low-mass-ratio circular cylinders on their mass ratio. Simulations were conducted at mass ratios representative of a cylinder in water: 1, 2, 5 and 10, and for reference to higher mass ratio VIV at a mass ratio of 50. It was found that, at low Reynolds numbers, Re ⩽ 400 , transversely vibrating circular cylinders exhibit three distinct regions of response: a primary response which occurs at and around resonance and is that normally associated with VIV, secondary or super-harmonically excited responses, and a tertiary, or infinite lock-in, response. The paper reports and discusses the response and vortex shedding characteristics of these three response regimes.