Soccer Ball Aerodynamics

Abstract

This chapter describes an interesting new application of computational science to sports engineering. The flight of sports balls (and in particular soccer balls) through the air is often a key part of the sport. In this work the physics behind the flight of soccer balls is introduced and discussed. This includes basic concepts such as boundary layer separation and the Magnus Effect. Computational Fluid Dynamics (CFD) and trajectory simulations are then combined to assess the erratic nature of different soccer ball designs, including the 2006 World Cup ball. It is found that both the lift and side force coefficients on a low- or non-spinning soccer ball vary significantly with orientation, which can result in varying erratic trajectories. These trajectories can also vary strongly with ball design and with the initial orientation of the ball. Ball consistency is one property that is often commented on by professional players. It is found that the most consistent balls are the ones with the optimum combination of amplitude and frequency of the varying force coefficients relative to the amount of spin. With the recent introduction of new manufacturing techniques, it should be possible to tailor ball surface patterns to give some interesting ball flights or to optimise consistency.