English Premier League’s new soccer ball is more stable and lags more – Eurasia Review
Scientists at the Faculty of Health and Sports Sciences at the University of Tsukuba used aerodynamic experiments to empirically test the flight properties of a new four-panel soccer ball adopted by the English Premier League this year. Based on the projectile and wind tunnel data, they calculated the drag and lateral forces and found that the new bullet was slightly more stable than previous versions, but couldn’t fly that far. This work can help improve the design of future sports equipment.
Sports players know that millions of dollars in salary and eventual sponsorship deals can be at stake in every game. Footballers often complain about the aerodynamic properties of the ball, as a random float in flight can turn a harmless shot into a goal. Old-fashioned soccer balls have 32 panels, with a mix of hexagons and pentagons. More recently, the best football leagues have experimented with 6-panel versions with stripes similar to those in volleyball. For the new season, the English Premier League introduced Nike’s Flight 2020 soccer ball, which is advertised as having molded grooves that provide consistent flight.
Now researchers at the University of Tsukuba have tested these claims with wind tunnel experiments. They measured the ball’s drag coefficient, as well as two previous models, based on the Reynolds number. The Reynolds number, an important parameter in fluid dynamics, controls the transition from smooth flow to turbulent flow. According to the author, Professor Takeshi Asai, “At low Reynolds numbers, smooth flow occurs because viscosity can dampen turbulence. At high Reynolds numbers, chaotic air vortices can lead to unstable and unpredictable flight patterns.
The team found increased drag at high Reynolds numbers for the new bullet. This led to a reduced flight range, but may also have reduced lateral forces that can destabilize the trajectory. This was especially true in the “asymmetric” orientation of the bullet, when one of the grooves was facing forward. “The smaller fluctuations in lateral forces and lift in Flight 2020 indicate that it is less likely to experience irregular trajectory changes, thus potentially leading to greater stability during flight,” says Professor Asai.
The team partially attributed this stability compromise at the expense of span to increased surface roughness. This finding may be useful in designing other sports equipment to increase the importance of skills and reduce the impact of luck.