Numerical explorations of the vortex-induced vibration of a streamlined box girder with water-filled barriers

The present study aims to investigate the charactefristics of vortex-induced vibrations (VIVs) of a streamlined box girder equipped with water-filled barriers (WFBs) through two-dimensional computational fluid dynamics (CFD) simulations. Initially, the VIV behavior of the bridge section is examined by considering various positions of WFBs and angles of attack (& alpha;), focusing on parameters involving vibration amplitude, surface pressure distri-bution, and flow field. Subsequently, in order to reveal the underlying VIV mechanism, the bridge section with WFBs commonly positioned was chosen to evaluate the contribution or inhibition of wind loads on specific regions around the bridge's surface to VIV, based on the pressure distribution and energy input process char-acteristics. The numerical results demonstrate that if the WFBs are positioned closer to the railing on the windward side of the bridge, as & alpha; shifts from negative to positive, the separated vortex on the upper surface of the bridge section tends to be larger. Additionally, the shedding of vortices at the tail of the deck becomes more pronounced, creating a greater periodic force on the bridge section and making it more vulnerable to VIV. The mean and standard deviations of pressure coefficients, as well as the predominant frequencies of the distributed pressures, are closely correlated with various stages of the VIV development process. The occurrence of VIV is actively triggered by the wind load acting on the upper surface upstream and lower surface downstream, while conversely, the wind load acting on the downstream of the upper surface and the upstream of the lower surface tends to inhibit the VIV. Moreover, it is worth noting that the growth rate of energy consumption on the downstream of upper surface is more significant than that of energy consumption in other regions, which makes a main effect on limiting the amplitude of VIV.