Numerical Investigation On Vortex-induced Vibrations Of Two Side-by-side Arranged Circular Cylinders At A Low Reynolds Number

The global ocean current energy is very abundant, however, the traditionalocean energy utilizing devices can hardly adapt to the low-velocity ocean currentswhich are widely distributed. Recently, the VIVACE (Vortex Induced VibrationAquatic Clean Energy), a device which can effectively convert the low-velocityocean currents into electrical energy by using the vortex-induced vibrations of acylinder array has attracted great interest from both academic and industrialcommunities due to its broad application prospects. Based on the above researchbackground, this paper numerically investigated the vortex-induced vibration ofthe simplest cylinderl array-two side-by-side arranged circular cylinders.A parallel LES code named CgLes, which has a high computing efficiency,is used for the numerical simulation of the vortex-induced vibration of twoside-by-side arranged elastically supported rigid circular cylinders inincompressible viscous fluid. The governing equations for fluid motion are theNavier-Stokes equations and the structure motion is governed by the Newton’ssecond law. And, the iterative immersed boundary method is applied to solve thefluid-structure interaction problem.The computational parameters of the simulation is that the Reynolds numberis Re=100, the cylinders’ mass ratio ism*2, the reduced velocity is from3.0to10.0, and the spacing ratio is from2.0to5.0. The dimensionless characteristicparameters of the vortex-induced vibrations, such as the lift coefficient, the dragcoefficient and the dimensionless amplitude, were presented. The effects of thereduced velocity and the spacing ratio on these parameters were systematicallyanalyzed. Three near-wake modes were observed and their relationships withthe vibration responses of cylinders, together with the coupling effects betweentwo cylinders, were analyzed and summarized.