TY - JOUR
T1 - Dynamics of a cylindrical beam subjected to simultaneous vortex induced vibration and base excitation
AU - Yari, Mahdi
AU - Acar, Gizem Dilber
N1 - Publisher Copyright: © 2024 Elsevier Ltd
PY - 2025/2/15
Y1 - 2025/2/15
N2 - In this study, the nonlinear dynamical behavior of a cylindrical beam subjected to simultaneous base excitation and vortex-induced vibration (VIV) is studied. Using a simplified Euler-Bernoulli beam model coupled with the van der Pol oscillator for the oscillating lift force, effects of VIV on the resonance frequencies of the beam are investigated. Interactions between the base excitation and VIV result in significant amplitude increases when the excitation frequency aligns with the cylindrical beam's natural frequency, particularly within the lock-in region. As flow speed increases, a notable frequency shift in peak amplitude, and a frequency-amplitude dependence are observed, signaling the nonlinear hardening effect of the oscillating fluid forces. In addition to cylinders fully immersed inside the fluid, those that are partially immersed inside the fluid are studied. Varying the submersion length of the cylinder impacts fluid force magnitude, reducing vibration amplitude and shortening the lock-in region. Additionally, for the system under coupled VIV and base excitations, vibration mitigation through the addition of local resonators is investigated. The introduction of resonators attenuates the primary vibration peaks while introducing new peaks at neighboring frequencies. The nonlinear effects on the frequency-amplitude dependence are minimized with increasing resonator mass, leading to wider vibration attenuation frequencies.
AB - In this study, the nonlinear dynamical behavior of a cylindrical beam subjected to simultaneous base excitation and vortex-induced vibration (VIV) is studied. Using a simplified Euler-Bernoulli beam model coupled with the van der Pol oscillator for the oscillating lift force, effects of VIV on the resonance frequencies of the beam are investigated. Interactions between the base excitation and VIV result in significant amplitude increases when the excitation frequency aligns with the cylindrical beam's natural frequency, particularly within the lock-in region. As flow speed increases, a notable frequency shift in peak amplitude, and a frequency-amplitude dependence are observed, signaling the nonlinear hardening effect of the oscillating fluid forces. In addition to cylinders fully immersed inside the fluid, those that are partially immersed inside the fluid are studied. Varying the submersion length of the cylinder impacts fluid force magnitude, reducing vibration amplitude and shortening the lock-in region. Additionally, for the system under coupled VIV and base excitations, vibration mitigation through the addition of local resonators is investigated. The introduction of resonators attenuates the primary vibration peaks while introducing new peaks at neighboring frequencies. The nonlinear effects on the frequency-amplitude dependence are minimized with increasing resonator mass, leading to wider vibration attenuation frequencies.
KW - Fluid-structure interactions
KW - Vibration mitigation
KW - Vortex-induced vibrations
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U2 - 10.1016/j.oceaneng.2024.120198
DO - 10.1016/j.oceaneng.2024.120198
M3 - Article
SN - 0029-8018
VL - 318
JO - Ocean Engineering
JF - Ocean Engineering
M1 - 120198
ER -