Study on the mechanism of the vortex-induced vibration ofa bluff double-side box section

At present, researchers mainly focused on the vortex-induced vibration (VIV) of the double-side I-shaped girder, while there are only a few literatures focused on the VIV of the bluff double-side box girder, especially the study on the synchronous pressure- and vibration- measured test for the bluff double-side box girder has not been reported. Therefore, in this study, the vibration-measured test, the Numerical Wind Tunnel Simulation, and the synchronous pressure- and vibration- measured test were conducted to study the VIV mechanism of the bluff double-side box girder. Firstly, a section model of the bluff double-side box girder was designed, and the vibration-measured test was conducted to study the influence of mass ratio, damping ratio, and aerodynamic countermeasures on the VIV of the bluff double-side box girder. Secondly, the Numerical Wind Tunnel Simulation was conducted to simulate the vorticity evolution of the bluff double-side box girder, which was used to help analyze the results of the synchronous pressure- and vibration- measured test. Finally, the synchronous pressure- and vibration- measured test was conducted to investigate the wind pressure distribution and aerodynamic forces on the surface of the double-side box girder, which was then used to study the VIV mechanism of the bluff double-side box girder by combining the simulated vorticity evolutions. So, when the VIV of the double-side box girder occurs, it is found that: there is a significant difference in the mean and fluctuating wind pressure between the upper and lower surfaces; moreover, at the leading and trailing edges, the aerodynamic forces contribute greatly to the VIV, the correlation between the aerodynamic forces and the vortex-induced aerodynamic forces is positive, and with the increase of this coefficient, it will lead to the more significant VIV.