Vortex-Induced Vibrations

The shedding of vortices in the wake of a body gives rise to fluctuating lift forces. A variety of vortex‐induced oscillation models are available in which the aeroelastic forces depend upon adjustable parameters fitted to match experimental results. By construction, those models provide a reasonable description of the observed aeroelastic motions. This chapter describes the across‐wind response of chimneys and towers with circular cross‐section. It schematically describes the forced vibration regime that corresponds to vibrations induced quasi‐statically by the vorticity in the wake of the cylinder, and the lock‐in regime that corresponds to vibrations due to aeroelastic effects. Turbulence in the oncoming flow decreases the coherence of the vorticity shed in the wake of the body, and reduces the magnitude of the across‐wind response.