Aerodynamics of an Australian Rules foot ball and Rugby ball

The aerodynamic behavior of a Rugby ball and an Australian Rules foot ball is complex and significantly differs from spherical sports balls due to their complex ellipsoidal shapes. Although prior aerodynamic studies have been conducted on soccer, tennis, cricket and golf balls, scant information about the Australian Rules and Rugby balls is available in the public domain. In order to understand the aerodynamic properties of Rugby and Australian Rules foot balls, experimental and computation studies have been undertaken for a range of speeds and yaw angles. The airflow around Rugby and Australian Rules foot balls was visualized and the average drag coefficients for both balls were determined and compared. Minor Reynolds number sensitivity at zero yaw angle was found in the experimental studies for both balls. However, significant Reynolds number variations were noted at yaw angles between 75^° and 85 ^°. In contrast, no major Reynolds number dependency was found in the Computational Fluid Dynamics (CFD) results for both balls.