梯度风场中高耸结构涡致振动响应时程分析

采用两参数振子模型,考虑梯度风场中高耸结构的气-固耦合相互作用;运用片条理论和差分法,建立了烟囱涡激振动多自由度体系非线性方程。直接在时域中求解多自由度非线性涡振方程,准确地反映涡激振动的“锁定”和振幅峰值效应,并在时域中分析了烟囱结构发生涡致振动的响应幅值、临界风速范围及其影响因素。

ANALYSIS OF VORTEX-INDUCED VIBRATION RESPONSES OF TALL CYLINDRICAL STRUCTURES IN GRADIENT WIND FIELD USING THE TIME-MARCHING APPROACH

A two-parameter lift-oscillator model is adopted to describe vortex shedding excitation on tall cylindrical structures. A theoretical model of a cylindrical structure with multi-degree-of-freedom is first formulated and the governing partial differential equations are solved using the finite difference approximation. Numerical analysis of vortex-induced vibration responses of cylinder structure is performed using the time-matching approach. The obtained results indicate that the present two-parameter lift-oscillator model can predict classical lock-in phenomena and the amplitude peak effect of cylindrical structures in gradient wind field. The influences of structural damping and model parameters on the vortex-induced vibration responses and critical wind speed of chimneys are discussed in detail.