Summary
This study numerically investigates the in-line flow-induced vibration (FIV) of elastically mounted elliptical cylinders undergoing forced rotations in a free-stream flow. The two-dimensional numerical simulations were conducted at a Reynolds number of 100. The cross-sectional aspect ratio of the cylinders varied from 1 to 0.25. The dimensionless rotation rate is set from low to high at 0.2, 0.5 and 1. Amplitude and frequency response are demonstrated in detail. The results demonstrate that the in-line vibration of rotating elliptical cylinder exhibits a substantially larger amplitude than the circular cylinder, on the order of one body diameter. In general, the major peak of the amplitude occurs when the rotating frequency locks to the structural natural frequency. The vibration response typically consists of harmonics associated with rotation as well as harmonics associated with vortex shedding, and a decrease in the aspect ratio results in the FIV to transition from vortex-induced to rotation dominance, while an increase in rotation rate reduces rotation dominance in turn.
