After more than thirty years making soccer balls for the World Cup, in 2006 Adidas started to mix things up. That year, the standard 32-panel stitched panels were dropped for a radical 14-panel design. In 2010, the number of panels fell to eight. This year the ball has only six panels.
Every time the design has changed, it has caused confusion and complaints from players that the ball moves differently – unexpectedly – in the air. How will this new ball fly?
On the technical side, there is a clear answer to this question: Scientist Simon Choppin undertook a detailed analysis of the aerodynamics of the ball. You can read his full presentation on The Conversation. But the short version is: this ball has much shorter seams than its predecessors. The seams impact the airflow over the ball, explains Choppin:
When air flows over a smooth, smooth object, it hugs the surface until it has passed completely through it, creating very little drag. The air flowing over a bullet behaves differently, it separates from the surface, creating an area of low pressure behind it – a wake. The low pressure region creates a drag force and slows the ball. At low speeds, the airflow is smooth (laminar) and separates early, creating a large wake and relatively high drag force. As speed increases, the air becomes more chaotic (turbulent), which helps it stay on the ball longer, reducing wake size and drag force.
At the 2010 World Cup, players complained the most about deflection of the balls: any small gust of wind or change in the air could cause the ball to spin and move. But this year’s prom might not have that problem, Choppin says. The seams on this new ball are deeper, he says, which will create more drag and stabilize the ball in the air.
On the subjective side, it’s almost guaranteed that players and coaches won’t be completely satisfied, they never are. Choppin’s final analysis: “While players and coaches may well find something wrong with the Brazuca, it’s definitely not a beach ball.”