Three dimensional numerical study of soccer ball aerodynamics at different spin conditions

Abstract

Aerodynamics of a soccer ball was studied with a three dimensional numerical approach using ANSYS Fluent. The ball used was a 32 panel soccer ball which was modeled in CAD and it was validated numerically by a 3D analyzing technique solving Reynolds-Averaged Navier Stokes (RANS) equations with k−ω BSL (Baseline) turbulence model. The flow was at zero angle of attack where velocity and spin conditions were varied to study the aerodynamic effects around the ball at different Reynolds Numbers and Spin parameters for rotation along two different axes. The validation procedure was able to predict the values of drag coefficient (Cd) reliably, it was also able to predict the wake structure along with velocity and pressure distribution. Both drag (Cd) and lift (Cl) coefficients were found to be highly dependent on spin parameter (Sp) values. The main limitation of the technique with the available computational resources was its inability to accurately predict boundary layer transition or growth, but despite this, several conclusions could be drawn regarding soccer ball aerodynamics. Spin parameter study contributes greatly to the technique of free kicks taken in the game of football. Exploitation of this phenomenon by players could have significant impact on the outcome of the game.