Two- and Three-Dimensional Simulations of Vortex-Induced Vibration of a Circular Cylinder

Numerical simulations of the interaction between a circular cylinder and its wake during both forced and free, vortex-induced, oscillation have been performed using a spectral element method in which the computational mesh was fixed to the cylinder and the Navier-Stokes equations solved in this accelerating reference frame. Thus far, work has focussed on cross flow, rather than in-line oscillations; with forced oscillation the lock-in phenomenon was observed over a range of reduced velocities near critical, while for the freely-vibrating cylinder the amplitudelimiting phenomenon observed in experiments was reproduced. A comparison of free and forced oscillation has been performed in which the forced oscillation amplitude and frequency were set to match those achieved in free vibration; the forces exerted on the cylinder by the fluid were similar in each case. Initial simulations were two-dimensional but the method may also be applied to three-dimensional flows by employing a spectral element/Fourier representation.