Full-scale measurement of wind pressure on the surface of an oscillating circular cylinders

• A comprehensive full-scale measurement campaign to study wind loading on circular cylinders is described.
• The effect of wind turbulence on the transition from the sub-critical to the critical Reynolds number range is highlighted.
• The effect of wind turbulence on the vortex shedding off circular cylinders is revealed.
• The effect of wind direction relative to the cylinder orientation on the flow structure is investigated.
• The outcome of the study can be used as a benchmark for investigation of wind loading on circular cylinders.

Under wind excitation, many slender structural members with circular cross sections have exhibited large-amplitude vibrations. The nature of some problematic vibrations remains to be fully understood. To investigate the excitation mechanisms that can cause the vibrations, an experimental campaign was conducted to measure simultaneously the wind pressure on the surface of a circular cylinder in the atmospheric boundary layer and the acceleration of this cylinder. The pressure and acceleration measurements were used to investigate the interaction between the cylinder and the turbulent wind in subcritical and critical Reynolds number ranges. The study revealed several effects of turbulence in wind in the atmospheric boundary layer on the critical transition, including the promotion of early critical transition, the attenuation of the single separation bubble, and the early cessation of the coherent vortex shedding. A coherent fluctuating axial flow component in the wake of circular cylinders yawed to the flow, which has been previously observed in wind tunnel tests in smooth flow and postulated to be critical for the onset of dry cylinder vibration at high reduced velocity, was not observed in the present experiment.