Wind-tunnel study of the effect of autorotation on feather and nylon badminton shuttlecock

An experimental investigation of the aerodynamics of popular models of synthetic nylon and duck/goose-feather shuttlecocks used in badminton, with and without autorotation, is conducted in a low-speed wind tunnel over a speed range of 20–70 m/s. The coupled influence of autorotation and structural deformation on their aerodynamic performance is examined. Synthetic shuttlecocks exhibit significantly larger structural deformation due to their more flexible skirt and, unlike the feather shuttlecock, buckle beyond a critical speed. Non-rotating shuttlecocks show a reduction in the cross-sectional area of skirt with increasing speed, accompanied by a corresponding decrease in drag coefficient. In contrast, rotating shuttlecocks demonstrate an initial decrease in drag at lower speeds, followed by an increase in both drag coefficient and cross-sectional area of the skirt at higher free-stream speeds. Rotation results in an increase in drag and eliminates buckling of skirt or delays it to higher speed. The autorotation speed increases approximately linearly with an increase in free-stream speed up to speeds where the change in the cross-sectional area of the skirt is small. Expansion of skirt increases autorotation speed while its contraction reduces it. Of the two models of nylon shuttlecock tested, one of them experiences very large autorotation speed and expansion of the skirt beyond a certain speed resulting in much larger drag coefficient compared to that for a feather shuttlecock.