A higher-order nonlinear oscillator model for coupled cross-flow and in-line VIV of a circular cylinder

ABSTRACT

In this paper, a higher-order nonlinear oscillator model has been proposed to predict the characteristics of the vortex-induced vibration (VIV) of a cylinder with two degrees of freedom. First, the vibration equations of the cylinder fixed by four symmetric springs were deduced based on the Lagrangian second kind of kinetic equation and the Taylor expansion formula of the binary function. Then, the fluctuating lift and drag were derived by using the discrete point vortex theory. Finally, the coupling model of the VIV was proposed by introducing the modified Van der Pol equation. On this basis, the VIV prediction of the cylinders with different mass ratios and damping ratios was carried out, and the results were compared with the experimental data to verify correctness and universality of the model. Besides, the sensitivity of the parameters in the model was analysed to investigate the predicting characteristics of the model systematically.

KEYWORDS:

• Vortex-induced vibration
• oscillator model
• nonlinear
• higher-order

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51509046], [grant number 51509045], [grant number 51739001].