Abstract
In this study, coupled responses of flow-induced vibration and rotation for an elastically mounted cylinder-plate body are numerically investigated at a low Reynolds number of 120. A wide vibrational reduced velocity range of Uy = 3–18 under four rotational reduced velocities Uθ = 5, 8, 12, and 18 are considered. The non-bifurcation responses, bifurcation only in rotation responses, and bifurcation in both vibration and rotation responses are identified. Typical vortex-induced vibration (VIV) responses are recognized when considering the passive rotations, different from the full interactions between VIV and galloping for the vibration-only case. As Uθ increases, the peak vibration amplitudes increase, the onset Uy of the lock-in region becomes larger, and the lock-in region is wider. The phase angles of displacements versus lift coefficients experience a jump from 0° to 180° in the lock-in region, and the larger the Uθ, the wider the Uy range of phase jump. Whether the instantaneous posture of the cylinder-plate body is streamlined or not is determined by oscillation amplitudes and phase differences between displacements versus rotation angles. Streamlined profiles can be achieved under small oscillation amplitudes or when the phase angles are nearly 90°. The 2S (two isolated vortices) vortex shedding mode dominates the initial and desynchronization branch, while the 2P (two pairs of vortices), 2S* (two isolated vortices with tendency to split), and 2T (two triplets of vortices) modes appear in the lock-in region. After the symmetry-breaking bifurcation, the reattachment behavior becomes simpler and the length of the recirculation region is significantly increased, as compared with those in non-bifurcation region. With the above study, a new method of improving energy harvesting from flow-induced vibration, by incorporating passive rotations simultaneously, is first introduced. It is found that passive rotations can enhance the vibration responses and thus lead to the increased output power and energy transfer ratio, although they make less contributions to the total power. Generally, this mechanical system presents a promising opportunity for energy harvesting through flow-induced vibration.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.