A hybrid experimental investigation of structural parameter effects on 2-DOF vortex-induced vibrations of a circular cylinder
Year: 2025
Type: article
Abstract: This study develops a two-degree-of-freedom (2-DOF) virtual physical framework (VPF) to investigate structural parameter effects on 2-DOF vortex-induced vibrations (VIV) of a circular cylinder. The framework ensures strictly planar vibrations with equal mass in both directions, while allowing flexible modification of m ∗ , damping ratio ζ , and natural frequency ratio f n ∗ under constant-Reynolds-number conditions. Results show that 2-DOF VIV exhibits a super-upper branch where the cross-flow (CF) amplitude is amplified compared with the 1-DOF case, and this amplification weakens as the mass ratio increases. At the same time, the in-line (IL) amplitude, synchronization range, and dominant frequency are reduced with increasing mass ratio. The phase difference increases gradually with reduced velocity ( U R ) and reaches its maximum at the CF amplitude peak. This maximum phase difference decreases as the mass ratio increases, and when U R further enters the lower branch, the phase difference drops to about 10°. Correspondingly, the trajectory evolves from right-opening figure-of-eight shapes to nearly straight CF-dominated lines as the IL response diminishes. The natural frequency ratio further alters the vibration features. At f n ∗ = 0 . 5 , both CF and IL vibrations are suppressed, whereas at f n ∗ = 2 . 0 , dual resonance occurs with amplified IL response, reversed asymmetric trajectories, and a pronounced third-harmonic component in lift force. Structural damping reduces both CF and IL amplitudes but has little effect on the dominant frequency. These findings provide necessary corrections to conclusions drawn from 1-DOF VIV and offer structural parameter references for engineering design. • Developed a hybrid framework for 2-DOF VIV tests with tunable structural parameters. • Conducted tests revealing the effects of structural parameters on 2-DOF VIV behaviors. • Identified the “dual resonance” at f n ∗ = 2.0 featured by third-harmonic lift forces.
Language: English
Subfield: Computational Mechanics
Field: Engineering
Domain: Physical Sciences
Open Access status: diamond
Funders: National Natural Science Foundation of China, National University's Basic Research Foundation of China, China National Funds for Distinguished Young Scientists, National Key Research and Development Program of China, Fundamental Research Funds for the Central Universities, National Science Fund for Distinguished Young Scholars
OpenAlex ID: W4416642494