Many variables are involved in the flight of a ball through the air and the Brazuca was tested for every possible variable making it the world’s most-tested ball. Any oversight in the aerodynamic design of the ball could make the ball’s flight pattern unpredictable like the Jabulani which was described as having “supernatural movements” (Wood).
Hong and Asai conducted several tests to research the effect of the panel shape on a soccer ball’s flight behavior with the Brazuca. They stated that when a ball is in mid-flight, the thin layer of air (boundary layer) surrounding it most affects the behavior of the ball. An effect pertaining to the boundary layer is knuckling – the wobbling of a ball when a ball is kicked with little/no spin which allows the seams to channel the air in an unpredictable way. The design flaw in the Jabulani was that when kicked, it had no initial spin which made it more susceptible to changes in the boundary layer (Wood). According to Wood, NASA scientists tested the performance of the Brazuca using a wind tunnel and water channel while using lasers and florescent dye to highlight and simulate the aerodynamic forces acting on the ball whilst in flight. Using these techniques, the speed at which the ball knuckles greatest can be found which was 30 mph. The Jabulani knuckled at 50 mph which is the average striking speed of a World Cup level player. This accounts for why the goalkeepers could not predict the trajectory of the ball. By restricting the Brazuca’s knuckling speed, the ball became much more predictable and stable in flight.
According to Bloomberg, at the end of the manufacturing process, each ball was fired at a flat metal plate using a shooting machine to ensure that each ball could survive 3500 impacts at 30 miles per hour. Then they were taken for computer testing where the ball was calibrated by a computer in 3D to ensure that it was of proper shape and size. Once the balls have passed these tests, the distribution process began.