Numerical modeling of the wind load of a two-dimensional cable model in rain-wind-induced vibration

Large amplitude rain-wind-induced vibration (RWIV) of stay cables has been widely reported in recent decades. As this large vibration might cause severe effects on stay cables and bridges, it has been become a worldwide concern in bridge and wind engineering. Extensive research has been conducted to investigate RWIV through field measurements, wind tunnel tests, numerical analysis, and the computational fluid dynamic method. In particular, to predict and avoid this large amplitude cable vibration, many numerical models based on the quasi-steady assumption have been proposed to numerically simulate the cable's responses. Recently, a new excitation mechanism has been proposed to explain RWIV through the interaction between the upper rivulet, boundary layer, and cable vibration, which indicated that the aerodynamic forces of the cable might also be related to the boundary layer state. In the present study, a new numerical model of the wind loads acting on a two-dimensional cable model during RWIV is established based on the boundary layer state. The established numerical model is then applied on a sectional model of stay cable which had been tested in a wind tunnel and the vibration responses are numerically calculated. The comparison between the calculated responses and the wind tunnel test results shows that this numerical model captured the main characteristics of RWIV. Finally, the parametric studies are conducted and the results show that the effective yaw angle, phase difference, cable diameter, damping ratio, and uniform coefficient have significant effects on the wind speed ranges or the vibration amplitude of the RWIV.