Geeks give Jabulani wind tunnel workout
Reuters - Wednesday 23 June 2010, 23:45
PASADENA - Aerospace engineers
at the California Institute of Technology normally test cars
and telescopes for aerodynamic differences in their high-tech
wind tunnel.
On Wednesday, they tackled a different object: the
controversial new Jabulani ball at this year's World Cup.
The brouhaha over the Jabulani - both on the pitch and in
the blogosphere - prompted scientists at the Nobel
Prize-winning Caltech to test differences between the
traditional ball and the upstart.
The two balls were put into the Lucas Wind Tunnel and
exposed to wind speeds of about 10 metres per second, slower
than a typical kicked ball. A smoke machine was used to
visualise to air movement around the ball.
How did the match end? Well, like many games at the World
Cup being hosted by South Africa, it was a draw.
Caltech assistant professor of aeronautics Beverley McKeon
said it was difficult to say which ball was better but she
noted the Jabulani's smoothness could create less drag and
therefore less predictable movement.
Created by sport manufacturer Adidas, the Jabulani is
seamless and so has a smoother surface, while the old ball has
deeper grooves between the panels, creating a more turbulent
airflow.
"It's very counterintuitive, but the rougher the ball, the
more predictable its trajectory," McKeon told reporters, adding
that a smoother ball with higher speeds would not follow as
clear a path.
CUP COMPLAINTS
Those findings match some of the complaints in the World
Cup community where players, coaches and fans have blamed the
Jabulani for bizarre trajectories and missed plays.
Spanish striker Fernando Torres complained about the ball
after he fluffed several scoring opportunities in Monday's 2-0
win over Honduras in Group H.
"We need to practise a bit more with this Jabulani because
we are having a bit of bother with it," Torres told reporters.
Amidst the controversy and tests like Caltech's, Adidas
maintained the new ball "meets or exceeds all FIFA approved
standards, and tests from the University of Loughborough
scientifically prove its unprecedented stable flight and
laser-like precision".
McKeon recommends players should just take more time to
adapt to the ball's differences.
Like any good scientist, she said more advanced testing is
needed to take into account other factors such as spin and
increased speed.
That did not stop her, however, from making her own call
about why England goalkeeper Robert Green farcically fumbled in
his team's opening 1-1 draw with the United States.
"Of course, I can blame it on the ball," she said.
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