Abstract
In this paper, the model of the VORTEX-INDUCED VIBRATION of a circular cylinder is investigated. The wake oscillator whose length alternates was proposed in author's previous paper. Now, author proposes "the Model of the Vortex-Induced Vibration of Circular Cylinder", which is represented by eqs. (10a, b, c). These equations are of the coupled-oscillation of the wake oscillator and the circular cylinder mounted elasticaly. The approximate periodic solutions of the steady state are obtained by eqs. (18a, b, c). The behaviors of these solutions are shown in Fig.1. It is indicated that the proposed model can be expressive of the properties of the vortex-induced oscillation of circular cylinder, i.e. i) synchronization, ii) sudden change of the phase shift between the lift and the displacement of cylinder, iii) double amplitudes response, iv) delay of the resonant velocity from the critical velocity, and from the velocity at which the maximum lift occurs. The resonant amplitude of the cylinder can be calculated approximately by eq. (19a). The results of eq. (19) are compared with the experimental results in Fig. 2. It is shown that both of the results are in good agreement. Fig. 5 to Fig. 12 are the comparison with the numerical solutions of eqs. (10a, b, c) and the experimental results. We can see that both are in good agreement not only in quality but also in quantity.
