Shuttlecock trajectory during spin serves

Spin serve is a serving technique in badminton that adds pre-spin before hitting the shuttlecock. This study examines the impact of spin serves on badminton players' shuttlecock trajectories, employing computational fluid dynamics and aerodynamic experiments for investigation. Three different pre-spin velocities are compared in this study, revealing three distinct phases in serve flights: (1) the turnover phase, (2) the oscillation phase, and (3) the stabilization phase. Pre-spin is found to affect the duration of the oscillation phase, while the turnover phase remains largely unaffected. Moreover, the effectiveness of the spin serve is highly dependent on the rotational direction of pre-spin velocity. This can be attributed to the shuttlecock's natural spin, which is induced by the inclination angles of its feathers. When pre-spin aligns with the shuttlecock's natural rotation, the oscillation phase shortens slightly, indicating a stabilizing effect on the trajectory. Conversely, when pre-spin opposes the shuttlecock's natural rotation, it significantly prolongs the oscillation phase, indicating a destabilizing effect. These findings underline the critical ability of the spin serve in shaping unpredictable trajectory characteristics.