2D numerical analysis on evolution of water film and cable vibration response subject to wind and rain

Under wind and rain, cables of cable-stayed bridges may vibrate with large amplitude known as rain–wind induced vibration (RWIV). According to the previous researches, the formation and oscillation of water rivulets around cable plays an important role in RWIV. In this paper, 2D coupled equations of water film evolution and cable vibration are presented for the first time based on the combination of lubrication theory and vibration theory of single-mode system. To reveal the mechanism of RWIV, the mutual influences of water film evolution, lift and vibration of cable under different wind speeds are analysed by numerically solving the coupled equations. In accordance with the experimental results, the numerical results show that RWIV only occurs in special wind speed and the period of water film evolution is close to cable natural period, which makes cable vibrate with large amplitude. Under too low wind speed, the inconspicuous variation of water film morphology leads to small amplitude of lift and cable vibrating like free vibration. And when wind speed is too large, cable also vibrates with small amplitude as the water film morphology and lift change with little periodicity. These confirm the conclusion that the resonance between rivulets and cable may be one of the main reasons for RWIV.