Cylinder is a typical component of offshore structures acted by various fluid forces, especially by viscous forces that may cause damage to structures due to vortex-induced vibrations. In this paper, the hydroelastic response of a circular cylinder-spring system to viscous flow is studied by numerical analysis. The method uses contravariant velocity fluxes on staggered grid and secondorder finite volume project discretization with GMRES/ILU technique to speed up the calculations. The motion of the cylinder integrated by Newmark-fl method is coupled with fluid flow calculation by ALE technique. The characteristic parameters of the vortex street such as Strouhal number and force coefficients can be predicted successfully. The "beat' and "lock-in' phenomena of the coupled system are revealed in the present calculations which agree well with existing experiment results. These calculations are instructive to further understanding of the hydroelastic dynamics of viscous flow.
Hydroelasticity of ship and ocean structure has been paid with much attention during the last two decades. Most of them deal with ideal fluid in waves. The problem in viscous flow, however, is another important field that affects structure significantly. Hydroelasticity in viscous flow is mainly concerned with the vortex induced vibration of cylinder in ocean engineering, for example, column of a fixed structure of flexible riser and cable connected to a floating structure of a towed vehicle, or vortex induced vibration of hydrofoil in steady flow around a controlling surface of a subsea vehicle. In such flow, fluid separation occurs, vortices shed from the structure exhibiting periodic fluid motion in certain Reynolds number range. The periodic forces acting on the structure will further introduce undesired vibration.
