Wind tunnel tests of autorotation of plate: The effects of tilt angle, chamfer form, and mass eccentricity

Windborne debris is one of the main factors that damage building structures in typhoon-prone areas, and plate-type debris is more common and concerning. Wind tunnel tests were conducted to study the aerodynamic characteristics of the rotating plate under the influence of tilt angle, chamfer form, and mass eccentricity. The aerodynamic characteristics including rotational speed, lift, drag, and moment coefficients were studied. Two states of steady speed and of a variant rotational speed increasing from 0 to a steady value were analyzed. The experimental results show that, in the steady state, the rotational speed and lift coefficient change slowly at first and then increase rapidly as the tilt angle increases (when the aspect ratios are greater than 1), and increase with the presence of the chamfers. The effects of different symmetrical chamfer forms on rotational speed and force coefficients are varied. In the acceleration state, the chamfers lead to the reduction of lift coefficient and the increase of moment coefficient at the same dimensionless rotational speed. The influence of mass eccentricity on rotational speed and force coefficients in both states is not obvious. Particularly, when both the buoyancy coefficient and eccentricity position are large, the plate cannot enter into full cycle. The Magnus effects of rotational plates with higher aspect ratios have been studied, and the aerodynamic data are useful for improving plate-type debris motion models. • Two states of accelerated and steady rotation are analyzed. • Complex rotation at different tilt angles is considered. • Chamfer increases the average rotational speed and lift coefficient at steady state. • Plates cannot rotate full circle when both buoyancy coefficient and eccentricity are large.