The world鈥檚 most famous cycling race, 聽the Tour de France, is getting underway again. 聽As they wind their way through the countryside, the over one hundred cyclists will聽group tightly together聽in a pack聽鈥� known as the peloton 鈥� to reduce air resistance and save their legs.
Now, thanks to the world鈥檚 biggest sporting simulation, we know exactly how much of an advantage they get from burying themselves in the peloton. Not only is less effort to be in the middle of the pack, it鈥檚 around ten times easier than previously thought.
To study the air flow around a group of cyclists, researchers created the largest ever sporting computer simulation. They divided a virtual peloton into 3 billion different cells for assessing wind resistance. This was then processed by a supercomputer that ran for 54 hours to calculate the interactions between riders, bikes, and the air around them.
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The results that popped up won鈥檛 surprise cycling fans 鈥� it鈥檚 best to be at the back of a triangular formation. However, it was previously estimated that this advantage is a wind resistance of around 50 per cent that of a lone rider, but the team found it to actually be a miniscule 5 per cent.
鈥淧ut it another way: it is as if a rider is cycling at 12 to 15 kilometres per hour in a peloton that is speeding along at 54 kilometres per hour. That鈥檚 why it feels right that riders expend so little energy,鈥� says Bert Blocken, who lead the project with colleagues at Eindhoven University in the Netherlands and KU Leuven in Belgium.
The calculations were then validated by using 121 physical models of cyclists in a wind tunnel. The models were 3D printed copies of a PhD student. Wind was then blown past them, and small pressure sensors were used to check the difference in air resistance at each point.
Cyclists often jostle position in the peloton, and Blocken鈥檚 work may help them to work out where to aim for. For example, the air resistance about 6 or 7 rows back in the peloton is similarly as advantageous as further back, but a cyclist would also have the advantage of being close enough to the front for any potential sprint finishes.
鈥淵ou can see immediately, from the car beside the riders, that some are hardly pedalling at all,鈥� says Tim Wade, at UK analytics firm Dimension Data, who spoke to New 杏吧原创 whilst following a peloton on the first day of the Tour de France.
The simulation may not yet account for enough real-world mess, such as variation in rider physique, bike design and the randomness of weather on the day, he says.
