This Monday's Tirreno-Adriatico doubles officially kicked off, with the S1 stage being a time trial, with a turnaround on the coastal road of Lido di Camaiore. Unsurprisingly, world time trial champion Filippo Ganna won the S1 stage, Remco Evenepoel finished second 11 seconds behind Ganna, and the much-anticipated Tour de France champion Tadej Poga ar finished third with an 18 seconds behind Ganna, a result that also met his expectations at the white road post-match press conference. At that time, he planned to keep the second difference within 10-20 seconds.
However, in addition to the Italian driver's 17th career time trial victory, some keen-eyed spectators noticed something was wrong – the roof of the team behind him was piled with spare vehicles.
QuickStep-AlphaVinyl followed behind Remco Evenepoel and stage-four Kasper Asgreen to take a similar approach. Meanwhile, the team car with two-time Tour de France champion Tadej Poga ar and stage-no.-5 Alex Dowsett had only one spare car on track.
In the S4 timed stage of the Paris-Nice race, the same was true of the team car behind the winner of the stage, Wout Van Aert, who was immediately behind him, with several spare cars loaded above him. And we're seeing more and more drivers with team roofs piled up behind them, as if this is already a routine operation.
We looked up UCI regulations and found that this practice was not illegal, that the UCI did not specify the number of spare fleets to be carried on the roof of the team, and that this operation did not appear to be an improvement made by Dan Bigham, an aerodynamic expert who had joined Ineos, for the team. It was confirmed that from the last stage of the 2021 Tour de Italy, the roof of the team behind Ganna had changed from one or two spare cars to piled bicycles.
In fact, in three of the four recent time trials he has played, the team cars behind him have been piled with bikes on top, namely the Etoile de Bessèges, the Tour de la Provence and this Monday's Double Sea Race.
So, did this kind of operation really help Ganna win the game? What does it get when a team car with a roof full of spare cars follows the driver? What is the scientific principle of this?
For this purpose, foreign media interviewed Richard Kelso, an adjunct associate professor at the University of Adelaide, who specializes in fluid mechanics, aerodynamics and sports engineering.
The Australian Cycling Team has been working with Kelso since 2008 for his aerodynamic expertise and has also been invited to be involved in the design of several helmets from KASK and SCOTT. In addition to the well-known wake effect of following a vehicle, he said, there are aerodynamic benefits to getting the car to keep up with the rider.
Kelso said: "I think the usual explanation is that any object that moves in the air pushes the air. In this case, the air pressure distribution in front of the car is altered as it moves forward, causing the air in front of the bike to be gently pushed forward. ”
"This means that the vehicle that follows behind the driver will actually push the air forward with the driver, and the air resistance around the driver will become smaller, although this effect is not obvious, but it can still have a certain effect, which can have a certain degree of influence on the driver in front."
Like any object moving in the air, both the rider and the vehicle following behind create a pressure field, with the high pressure zone in front and the low pressure zone in the back. The difference in air pressure between high and low pressure zones is the cause of resistance.
Theoretically, when an object (in a race, UCI stipulates that the team car can follow another object about 10 meters behind the driver), the high pressure area in front of the team car will affect the low pressure area behind the driver, thereby helping the driver reduce air resistance.
"Depending on the distance between the driver and the team car, the driver is pushed by the air in front of the team car," Kelso explains.
"The most obvious effect is directly in front of the vehicle, where the air basically moves with the vehicle, while the smallest effect is infinitely far in front of the vehicle. Therefore, 10 meters ahead, there will be a very small push to move with the driver, although this push is small, but it is enough to have an impact on the rider in front, reducing the driver's forward resistance. "
Kyle indexed the words of Belgian professor Bert Blocken, who has done a lot of research on the benefits of following the driver 10 meters behind the driver.
He found that a car that followed 10 meters behind could help the rider in front reduce drag by 0.23%, which is equivalent to 3.9 seconds of gain by riding 50 kilometers. For this 14-kilometer track, it can save about 1 second. "
Well, this second is what Bogacha and Dorset are likely to gain in the game. Although the bike "wall" on the team car behind Ganna and Efernapple will only generate an extra shred of revenue.
"Because the bikes are piled up on the roof, the vehicle actually looks more like a box truck, and broadly speaking, it's actually like having a team car that doubles in height," Kelso said. If the bikes are stacked full enough, and the gaps between them are small enough, it can cause a big obstacle to the air flow through.
"Basically, if you want to get the most out of it, you need an object that resembles a box shape to have an aerodynamic effect, ideally flat on the front, sharp edges, and so on, to maximize the resistance of the vehicle behind you, to have the greatest impact on the air in front of you." Kelso added in response to a joke by Greg Henderson, performance coach of the Israeli Botai team, who joked that he would use a team bus to follow Dorset in the future.
Kelso concludes that for Ganner and Efennepur, having their team cars full of bikes may give them a few more seconds than their opponents.
"Considering that there are all the bikes on it, maybe that time can count as 2 seconds," Kelso said. "Maybe this would buy the driver a few seconds, but that's ideal, in fact, the team car can't be 10 meters behind the driver the whole time. So I don't think that really affects the outcome of the game, of course, nobody knows what the outcome will be until the end of the game. "
The original intention of the Ineos and Quicks pacers was to give their drivers a little advantage, even a slight gain that might not change the end result. However, their approach gives us another look at in future time trials.
During the time trial, Ganna offered a choice of 10 spare cars, whether to cater to the needs of his vehicles of different sizes or whether the team's car wanted to be able to quickly leave the race after the race, if it was the latter, it might be completely irrelevant to aerodynamics.
Edit: Johnny
Image source: Double Seas @ Paris-Nices Official Media