柔性圆柱体横流与顺流方尙涡激振动耦合响应特征研究

A numerical investigation of the vortex-induced vibration response characteristics of a flexible circular cylinder under external flow was conducted based on the wake-oscillator model. Different flow profile parameters and aspect ratios (L/D) were considered in the study. First, a three-dimensional theoretical model was established for the vortex-induced vibration of the flexible cylinder, in which the coupling between the cross-flow (CF) and in-line (IL) directions was taken into account. Subsequently, flow excitation models in both CF and IL directions were developed based on the wake oscillator model, and the coupling between the flexible cylindrical structure and the external flow field was established based on vector analysis theory. The coupled model was solved numerically by combining a second-order central difference scheme with a backward difference scheme. Finally, a systematic analysis of the vortex-induced vibration response characteristics of the flexible cylinder was conducted under different flow profile parameters and aspect ratios. The numerical results indicate that, in terms of vibration displacement response, the vibration amplitudes in both the in-line and cross-flow directions decrease with increasing flow profile parameters. The structural vibration consists of a combination of standing and traveling waves, with the traveling wave characteristics becoming more pronounced as the flow profile parameter increases, particularly in the IL direction. In terms of vibration frequency response, for both uniform and linear shear flows, the structure exhibits a single-frequency feature in the CF direction, while a multiple-frequency response is observed in the IL direction, with the dominant frequency being approximately twice that of the CF direction. For the linear shear flow, compared with the CF direction, the IL-direction vibration response contains more peak frequencies with a more dispersed energy distribution. In addition, the dominant frequency and other peak frequencies participate intermittently in the IL vibration response.