Vortex-induce Vibrations of Two Degrees of Freedom Sprung Cylinder with a Rotational Nonlinear Energy Sink (r-nes): a Numerical Investigation

Abstract Vortex-induced vibration (VIV) is a common fluid-structure interaction (FSI) phenomenon in the field of wind engineering and marine engineering. The large-amplitude VIV has a marked impact on the slender structure in fluids, at times even destructive. To study how the VIV can be controlled, the dynamics of a rigid cylinder attached to a rotational nonlinear energy sink (R-NES) is investigated in this paper. This is done using a two degrees of freedom (2-DOF) Van der Pol wake oscillator model adapted to consider a coupled vibration in cross-flow and streamwise directions. The governing equation of R-NES are coupled to the wake oscillator model, hence a flow-cylinder-NES coupled system is established. While exploring the dynamics of the cylinders with different mass ratios under the action of R-NES, it was found that the R-NES deliver better performance in suppressing the VIV of a cylinder with high mass ratios than that of a low mass ratios cylinder. The effect of the distinct parameters of R-NES on VIV response was also systematically investigated in this study. The results indicate that higher mass parameter and rotation radius can lead to improved performance, while the effect of the damping parameter is complex, and appears to be linked to the mass ratio of the column structure.

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Interaction of nonlinear energy sink with a two degrees of freedom linear system: Internal resonance

Journal of Sound and Vibration ◽

10.1016/j.jsv.2009.11.025 ◽

2010 ◽

Vol 329 (10) ◽

pp. 1836-1852 ◽

Cited By ~ 32

Author(s):

Y. Starosvetsky ◽

O.V. Gendelman

Keyword(s):

Linear System ◽

Internal Resonance ◽

Degrees Of Freedom ◽

Nonlinear Energy Sink ◽

Two Degrees Of Freedom ◽

Energy Sink ◽

Nonlinear Energy

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Annihilation of high-amplitude periodic responses of a forced two degrees-of-freedom oscillatory system using nonlinear energy sink

Journal of Vibration and Control ◽

10.1177/1077546312456226 ◽

2012 ◽

Vol 19 (16) ◽

pp. 2401-2412 ◽

Cited By ~ 14

Author(s):

Zahra Nili Ahmadabadi ◽

Siamak E Khadem

Keyword(s):

Degrees Of Freedom ◽

Nonlinear Energy Sink ◽

Oscillatory System ◽

High Amplitude ◽

Two Degrees Of Freedom ◽

Energy Sink ◽

Nonlinear Energy

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Fluid nonlinearities effect on wake oscillator model performance

MATEC Web of Conferences ◽

10.1051/matecconf/201814804002 ◽

2018 ◽

Vol 148 ◽

pp. 04002 ◽

Cited By ~ 2

Author(s):

Victoria Kurushina ◽

Ekaterina Pavlovskaia

Keyword(s):

Structural Damage ◽

Degrees Of Freedom ◽

Model Performance ◽

Cross Flow ◽

Resonance State ◽

Oscillator Model ◽

Mass Ratio ◽

Wake Oscillator Model ◽

Wake Oscillator ◽

Wide Range

Vortex-induced vibrations (VIV) need to be accounted for in the design of marine structures such as risers and umbilicals. If a resonance state of the slender structure develops due to its interaction with the surrounding fluid flow, the consequences can be severe resulting in the accelerated fatigue and structural damage. Wake oscillator models allow to estimate the fluid force acting on the structure without complex and time consuming CFD analysis of the fluid domain. However, contemporary models contain a number of empirical coeffcients which are required to be tuned using experimental data. This is often left for the future work with the opened question on how to calibrate a model for a wide range of cases and find out what is working and is not. The current research is focused on the problem of the best choice of the fluid nonlinearities for the base wake oscillator model [1] in order to improve the accuracy of prediction for the cases with mass ratios around 6.0. The paper investigates six nonlinear damping types for two fluid equations of the base model. The calibration is conducted using the data by Stappenbelt and Lalji [2] for 2 degrees-of-freedom rigid structure for mass ratio 6.54. The conducted analysis shows that predicted in-line and cross-flow displacements are more accurate if modelled separately using different damping types than using only one version of the model. The borders of application for each found option in terms of mass ratio are discussed in this work, and appropriate recommendations are provided.

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Evaluation of Energy and Power Flow in a Nonlinear Energy Sink Attached to a Linear Primary Oscillator

Journal of Vibration and Acoustics ◽

10.1115/1.4044450 ◽

2019 ◽

Vol 141 (6) ◽

Cited By ~ 2

Author(s):

Christian E. Silva ◽

Amin Maghareh ◽

Hongcheng Tao ◽

Shirley J. Dyke ◽

James Gibert

Keyword(s):

Power Flow ◽

Degrees Of Freedom ◽

Nonlinear Energy Sink ◽

Primary System ◽

Combined System ◽

Analytical Treatment ◽

Different Types ◽

Energy Sink ◽

And Performance ◽

Nonlinear Energy

Abstract The objective of this study is to develop a novel methodology to assess the energy flow between a nonlinear energy sink (NES) and the primary system it is attached to in terms of energy orientation, which is directly related to the sign of the power present on the primary system. To extend the work done in previous studies, which have focused primarily on the analytical treatment, characterization, and performance evaluation of NES as passive nonlinear dampers for structures under different types of excitations, this study incorporates a methodology for determining whether energy is entering or leaving a primary oscillator when interacting with an NES, by means of considering the power flow of the primary oscillator. Several current measures for evaluating the effectiveness of the NES at extracting and dissipating energy irreversibly are considered through numerical simulations of systems with different damping cases of the NES. Each case provides a different dissipation scenario in the combined system, which is subjected to different types of base excitation signals such as impulse and seismic records. The methodology is further validated experimentally using a two degrees-of-freedom system with an NES attached to the second mass. Comparisons of the modeled responses versus the measured responses are provided for several physical damping realization scenarios in the NES.

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