Experimental simulation of downburst-like outflows and the associated dynamic properties of a self-supported transmission tower

Abstract

This paper focuses on the replication of a downburst outflow with the plane wall jet approach and reports on the response of an aero-elastic model of a self-supported tower subjected to that outflow. The stationary and non-stationary wall jet flow is studied through velocity measurements at various elevations and downstream distances. The results indicate that the normalized mean velocity profiles from the current steady flow tests have a good agreement with the empirical models of the vertical profile for downbursts. The influence of the Reynolds number (Re) on the decay weakens when Re > 30,000. A rotating-gate device can generate the primary characteristics of the non-stationary downburst-like wind. The power spectral density of the residual turbulence from the generated non-stationary wind is consistent with the synoptic wind. The full-scale downburst recorded from the Andrews Air Force Base is used as the target event to verify the experimental procedure. The aero-elastic testing results show that the resonance contribution can reach more than 60% of the total fluctuating response of tower. There is no clear trend for the displacement and acceleration response with the change of downstream distance of the tower.