The Aerodynamics of Cricket Ball Swing

Abstract

The technique of swing bowling is used in the sport of cricket to gain an advantage over the batter, and improve a team’s chance of winning a match. The current best practice for swing bowling is based on anecdotal evidence, with little consensus on the optimal strategies. Bowling technique, the condition of the ball and atmospheric conditions are all considered important for swing, yet there is little quantification of these factors even in elite cricket. Previous experimental studies have not provided a description of swing that aligns with measurements of on-field swing made using ball-tracking technology. This research looks to provide clarity on the physical mechanisms behind swing bowling for new and used cricket balls. Appropriate boundary conditions are measured in field tests, and applied to experiments so that results represent on-field swing. Wind tunnel tests are performed which measure the changes in the aerodynamic force coefficient, CF. The relevant findings are related back to cricket through tools for use in the professional game. For new cricket balls, it is shown that conventional swing has a magnitude of 0.3