The heat is on for cyclists in the London velodrome

The velodrome which will host the track cycling events at the 2012 Olympics in London is now open. The facility is the first to open in the Olympic village and has been given the title of the ‘best in the World’. When a country hosts a major sports event, such as the Olympics, they want to show off their facilities to the world and create a lasting legacy. This usually means impressive architecture, such as the Bird’s Nest stadium in Beijing, or state-of-the-art transport links and infrastructure. The engineers behind the new velodrome have gone a step further by designing the facility specifically to allow the cyclists to ride faster and hopefully break world records. In addition to a specially designed track, the air temperature in the velodrome will be higher than usual to reduce aerodynamic drag acting on the cyclists. For those of you worried about breaking a sweat whilst you watch, don’t worry the spectator area will be nice and cool!

Cycling aerodynamics

The drag force acting on a cyclist (or indeed any object)  is defined as follows;

 

Air density reduces as temperature increases, as shown in figure 1. Therefore, raising the temperature inside the velodrome will reduce the drag force acting on the rider, allowing them to go faster. Figure 1 shows how temperature effects the drag acting on a track cyclist using typical values for the area and drag coefficient.

 
Figure 1 Left: relationshiop between air density and temperature, Right: predicted drag force acting on a cyclist

Reducing the resistive force acting a cyclist will give the greatest time advantage on longer distance events, such as the individual pursuit which is raced over 4 km. An in house track cycling research tool, developed by Dr Rich Lukes, was used to predict the effect of increasing the air temperature in the individual pursuit. Increasing the temperature from 20 degrees to 25 degrees produced a time advantage of approximatley 1.4 s over 4 km. The interesting thing to note is, the higher temperature will aid all athletes in breaking records, whilst giving them no advantage over their immediate competitors.

Conclusion

Sports engineers are renowned for giving individual athletes or teams an advantage by improving their equipment. The engineers behind the 2012 velodrome  have gone a step further by building a facility which should increase the performance of all competitors. In particular, the air temperature inside the velodrome will be higher than usual to reduce the drag force acting on the cyclists. Increasing the temperature from 20 degrees to 25 degrees would give a world-class cyclist a performance advantage of approximately 1.4 s over 4 km. My prediction, records will be broken in the velodrome in 2o12, particularly in the longer distance events.

Tom
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About Dr Tom Allen

Dr Tom Allen is a lecturer in engineering design at Sheffield Hallam University. He leads the University's BSc (Hons) Sports Technology course and is the associate editor of Sports Engineering.

8 Responses

  1. Ed

    A very good article indeed and very interesting to read. It’s certainly very warm in there as I was there over the weekend.

    Whilst I do not dispute the reduced drag due to higher temperatures I’d be interested to know what effects a couple of other effects of the heat would have on performance.

    Firstly to the actual athlete themselves and how quickly they tire in the elevated temperature. I’m sure this elevated temperature will make the athletes tire quicker than if in a cooler environment or at least surely make it harder to get the hydration levels right before the event if they are waiting around for several hours before their particular event.

    Secondly the effect of the extra grip the tyres are likely to have on the track due to the increased rubber temperature and whether this would lead to any increase in rolling resistance of the bike?

    I am an engineer but certainly have little expertise in this field. Would be interesting to get an answer however (I’m sure the first point might be slightly more athlete specific however).

  2. Mike

    Good article. I have some questions. How is the lower wind resistance effected? Is it because air is less dense on the track because hot air rises? Would that then mean there also less oxygen intake per breath for the cyclist at the track level? Would you then predict that world records would be broken in sprint races rather than the long distance ones? And if the intention of the raised stadium temperature is to get world record times, would it not be better to set different temperatures depending on the length of the race rather than just setting the temp 5 degrees higher (ie. higher temps for sprints, lower temps for long distances)?

  3. Anonymous

    An exiting article from a sports engineering perspective. Question:
    Could a negative ionised air consumption be used in this “closed” invironment to give the individual, advantages in terms of breaking records, if this truly is the engineers whish?

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