Simultaneous CFD evaluation of VIV suppression using smaller control cylinders

摘要

Two-degree-of-freedom vortex-induced vibrations (VIV) of a circular cylinder with and without two smaller control cylinders are investigated numerically by computational fluid dynamics (CFD) models coupling with a fluid-structure interaction (FSI) computational method. The numerical model is validated against experimental data of VIV of an isolated cylinder in uniform current. The study is aimed to investigate the effect of smaller control cylinders on VIV suppression. The trajectories of cylinder motion, amplitude response, and temporal evolution of vortex shedding and streamlines are obtained by conducting a series of simulations. And the effect of Reynolds number, located angle and rotational rate of small control cylinders are discussed in detail. It is found that placing small cylinders at 450 to the downstream vector can achieve a good suppression effect, but the effect is different at different Re. Rotating control cylinders with a reasonable rotation velocity can further enhance the VIV suppression by injecting enough momentum into the boundary layer of the main cylinder. The best effect is found at U-c=10, which has a 64.56% reduction in the transverse vibration response. (C) 2015 Elsevier Ltd. All rights reserved.