圆柱体横流与顺流方向涡激振动耦合模型研究

The coupled model of combined Cross-Flow (CF) and In-Line (IL) Vortex-Induced Vibration (VIV) of a rigid cylinder was studied based on the wake oscillator model. The model of the structural oscillator and wake oscillator considering structural geometrical nonlinearities in CF and IL directions was established firstly, and then the model was discretized and solved based on a standard central finite difference method of the second order. After that, the credibility of the present numerical model was validated by comparing with other researchers' experimental results. Finally, the VIV response amplitudes in CF and IL directions and VIV trajectories with different mass ratios, different structural damping ratios and different geometrical nonlinearity coefficients were compared. The results show that as the mass ratio increases, the vibration amplitudes in both CF and IL directions decrease, and the lock-in regions become smaller. As the structural damping ratio increases, the amplitudes in both CF and IL directions decrease.However, the lock-in regions become wider. As the reduced velocity increases, the VIV trajectories display oblique "8" figure, "crescent moon" figure and upright "8" figure in sequence. As the geometrical nonlinearity coefficients increase, the abrupt decrease from the upper branch to the lower branch in CF and IL VIV amplitudes become more obvious.