Computed Flow around an Oscillating Circular Cylinder

Abstract

The oscillation of a circular cylinder in a uniform flow is not only one of the basic subjects of fluid dynamics, but is also a very important problem in fluids engineering. In the present paper, the cross-flow and in-line vibrations of a two-dimensional circular cylinder were studied numerically. Both the forced and free vibrations were examined. Vortex shedding became synchronized with the forced cross-flow vibration at a frequency close to that of the Strouhal number of a stationary cylinder. With forced in-line vibration, vortex shedding began to synchronize with the frequency and also one half that of a circular cylinder at a higher vibration rate. With free vibration, the cross-flow vibration was excited when the natural frequency of the cylinder was near the stationary Strouhal number, and in-line vibration was observed near the natural frequency at around twice the stationary Strouhal number.