Vortex induced vibration and vortex shedding characteristics of two side-by-side circular cylinders of different diameters in close proximity in steady flow

This paper presents results of a numerical study of vortex-induced vibrations of two side-by-side circular cylinders of different diameters in steady incompressible flow. The two-dimensional Reynolds-averaged Navier–Stokes equations with a SST k–ω turbulence model are solved using the Petrov–Galerkin finite element method and the Arbitrary-Lagrangian–Eulerian scheme. The diameter ratio of the two cylinders is fixed at 0.1 and the mass ratio of both cylinders is 5.0. Both cylinders are constrained to oscillate in the transverse direction only. The Reynolds number based on the large cylinder diameter and free stream velocity is fixed at 5000. The effects of the reduced velocities of the cylinders on the vibration amplitude and vortex shedding regimes are investigated. It is found that for the range of parameters considered, collision between the two cylinders is dependent on the difference of the reduced velocities of the cylinders. Presence of the small cylinder in the proximity of the large one appears to have significant effects on the vortex shedding regime and vibration amplitude of the large cylinder.