A study of spin effects on tennis ball aerodynamics

Due to complex surface structure, the aerodynamic behaviour of a tennis ball is significantly different compared to other sports balls. This difference is more obvious when spin is involved. Although several studies have been conducted on drag and lift in steady state condition (no spin involved) by the authors and others, little or no studies have been conducted on spin effect. It is known that the spinning can affect aerodynamic drag and lift of a tennis ball thus the motion and flight of the ball. The primary objective of this work was to study the effect of spin using experimental and computational methods. Several new tennis balls were used in experimental study as function of wind speed, seam orientation and spins. A simplified model of a tennis ball was used in computational study using commercial software ‘FLUENT’. The simulation results were compared with the experimental findings. The study shows that the spin has significant effects on the drag and lift of a new tennis ball, and the averaged drag coefficient is relatively higher compared to the non- spin condition. The study has also found a significant variation between CFD and EFD results as the complex tennis ball with fuzz elements was difficult to model in CFD.