Comprehensive investigation of vortex-induced vibration and aerodynamic forces characteristics in tandem rectangular sections

The aerodynamic interference effects between tandem structures are significant and can adversely affect both the wind-induced vibration characteristics and the aerodynamic performance. To investigate these effects, wind tunnel tests and numerical analyses were performed on chamfered and non-chamfered rectangular sections. Different spacings 2.9B-5.0B (B represents section width) were considered. Wind tunnel tests evaluated the vortex-induced vibrations (VIV) amplitude and wind speed range. Numerical analyses examined the aerodynamic characteristics and flow structure. It indicates that chamfered corners can enhance the VIV performance of a single structure. While the maximum VIV amplitude in the upstream column with chamfered corners, at spacing of 2.9B, increases by 288% than that of a single section, and gradually decreases as the spacing increases. The maximum VIV amplitudes of upstream rectangular section are slightly increased. For downstream section, the maximum VIV amplitude is much smaller than that of a single section. The mean drag coefficient of downstream cylinder consistently remains lower than that of upstream section, although it slightly increases with larger spacing. Chamfered corners cause upstream wake vortices to contract and downstream wake vortices to elongate along the flow direction. At spacing 2.9B, vortices shed from the upstream section just impact the windward side of downstream section. Compared to the upstream section, the vortex core center of the downstream column section is closer to its leeward surface, and the recirculation length is shorter than that of the upstream section. The research findings can serve as a reference for wind-resistant design of similar structures.