The beginning of branching behaviour of vortex-induced vibration during two-dimensional flow

To date, the majority of studies of vortex-induced vibration (VIV) of a cylinder constrained to oscillate transverse to the freestream have been experimental, and at a Reynolds number, Re, where the flow is inherently three-dimensional. At these higher Re, an upper and lower branch of response are observed. Mostly, these branches have not previously been investigated at lower Re where the flow is two-dimensional. Therefore, two-dimensional simulations have been performed at Re = 200 to thoroughly investigate the response of a cylinder to VIV. It was found that two regimes of response were present, similar in nature to the upper and lower branch at higher Re. While some differences were present, it was found that the genesis of the higher-Re flow behaviour was present in the low-Re two-dimensional flow, with evidence for this found in the amplitude, frequency and phase response of the cylinder. (c) 2006 Elsevier Ltd. All rights reserved.