from the things-that-sound-like-bazooka dept.
Aerodynamics is the study of how air and liquids, referred to collectively as "fluids" in aerodynamics research, flow around objects. Engineers at NASA's Ames Research Center in Moffett Field, California, a world leader in fundamental aerodynamics research, possess an in-depth understanding of how fluids flow around simple three-dimensional shapes such as cylinders and spheres. With this knowledge, engineers can predict how even the minor alterations in these basic shapes change flow patterns.
The previous World Cup ball, the Jabulani, was described as sometimes demonstrating "supernatural" movements. It was beloved by strikers but hated by goalkeepers because, when kicked with little or no spin, the ball "knuckled," giving strikers a greater chance of scoring. Knuckling occurs when, at zero or near-zero spin, the seams of the ball channel airflow in an unusual and erratic manner making its trajectory unpredictable.
To address the unpredictability of the Jabulani ball, Adidas worked with hundreds of players to develop the Brazuca football. A traditional football has 32 panels, the Jabulani has eight panels and the Brazuca has only six. Despite having fewer panels, the finger-like panels on the Brazuca increase the seam length, compared to previous World Cup balls. The seams are also deeper than those of the Jabulani and the panels are covered with tiny bumps; all of these factors influence the ball's aerodynamics.
The smoother a ball is, the higher the speed at which the knuckling effect occurs. However, with the increased roughness of the Brazuca, this critical speed for maximum knuckling is reduced to about 30 mph. This is well below the typical kicking speed of a World Cup-caliber player, which is about 50 to 55 mph. So it is expected that the 2014 World Cup ball will have a more predictable flight path at typical striking speeds.
Will this make the game less exciting? The answer is no. With a new understanding of the aerodynamics of the Brazuca football, the audience, especially kids, can better appreciate the feats of skill on the field. Elite athletes will continue to manipulate the ball in amazing ways. They don't have the terms like "Bend it like Beckham" for nothing.
If given the opportunity, and/or an interest in pranks, what creative "adjustment" would you make to the balls other sports use: basketball, football (American), golf, baseball, tennis, etc?