Fifa World Cup 2014 is underway and before we all are consumed by the excitement of who will win this tournament, it appears that everyone is concerned with is the football that is being used in the WC. The reason for such interest can partly be attributed to the football used in last WC which didn’t really get along with all the players and Brazilian striker Luis Fabian termed it supernatural when it came to ball’s movements. The current football is named Brazuca, comes from Adidas and was manufactured in Pakistan.
You would be surprised to know about the amount of effort and research put into the creation of a football for this world famous tournament. The football is not just a sphere but also an object whose aerodynamics needs to be studied carefully and adjustments need to be made. The flight of a ball through the medium (air) is a study in itself that involves aerodynamics forces and a myriad of scientific phenomena.
In simplest words; a thin layer made of air is formed on the ball’s surface when it moves in air and this layer is known as boundary layer, covering all of the football. The pressure distribution on the surface can make a ball act crazy (remember the last WC?).
The toughest challenge that Adidas faced was coming over the knuckling effect (ball hit without spin and the path being determined by the pressure distribution). The solution was to roughen the surface of the ball and use 6 panels while stitching the football together.
NASA scientists at the Ames Research Center decided to test the Brazuca and employed a wind tunnel, water channel in collaboration with lasers and florescent dye to clearly show and simulate the forces that were acting on the ball when it was in flight. Rabi Mehta, Chief of the Experimental Aero-Physics Branch, said; ‘What we are looking for in the smoke patterns is at what speed the smoke patterns suddenly change. This is when the knuckling effect is greatest.’brazzuca being tested
The findings concluded that for Brazuca, the optimal knuckling speed is only 30Mph whereas, the average strike speed of a WC player is 50-55 Mph and therefore, with the restriction on Brazuca’s knuckling speed, the ball is far more stabilized and predictable. Mehta said; ‘the players should be happier with the new ball. It is more stable in flight and will handle more like a traditional 32-panel ball.’aerodynamics
NASA’s team is not the only team that has been analyzing the Brazuca, we have a team from MIT that has been scrutinizing the ball. According to this team’s finding, the rougher surface allows this particular ball to handle the Magnus Effect as well. For those of you who are not aware of this phenomenon, Magnus Effect is when the ball spins in opposite direction from where it has been shot to spin.