In this blog post, we look at how advances in sports technology have affected performance and fairness, using the example of high-tech swimsuits.
In 2008, when the swimwear company Speedo developed and unveiled a swimsuit using cutting-edge materials and technology called ‘Laser Racer,’ the term ‘technological doping’ began to be used in the swimming world. Of the 25 world records set at the 2008 Beijing Olympics, 23 were set by athletes wearing these high-tech swimsuits, giving rise to the term ‘Laser effect.’
Many athletes wore these ‘Lazer Racer’ full-body swimsuits at the Beijing Olympics, and various world records were broken. As this issue continued, the International Swimming Federation banned the use of high-tech swimsuits. What effect did these high-tech swimsuits have that caused such competition results and controversy?
As we know from experience, when a person moves in water, they encounter resistance from the water. This resistance includes resistance caused by water hitting the body (shape resistance), resistance caused by water passing over the surface of the body (surface friction resistance), and resistance caused by the difference in pressure between the front and back of the body (pressure resistance).
In order to reduce shape resistance, it is necessary to reduce the amount of contact between the body and the water, which is why people lie face down in the water to ‘swim.’ Naturally, swimming is faster than walking in water. In swimming competitions, the athletes swim using the same stroke and their physical conditions are not significantly different, so there is no significant difference in speed. In order to create a small difference, athletes train and build their bodies.
However, problems arose with surface friction resistance and pressure resistance. Previously, most athletes swam with very little clothing, so there was no significant difference here. At most, they tried to reduce friction by trimming their body hair. However, with the advent of full-body swimsuits, the surface of the body was changed to resemble that of a fish. This reduced friction between the body and the water, which in turn reduced the pressure difference between the front and back of the body, overcoming a problem that had previously been insurmountable.
The nature of fluid dynamics is well illustrated by this long story of swimsuits and water. Everything that flows around us can be simply described as a fluid, with water and air being the most common examples. Fluid dynamics is the analysis of phenomena that occur between fluids and objects, as described above. In swimming, the swimmer is the object and the water is the fluid. The three types of resistance mentioned above can exist between all fluids and objects. This is true not only when a swimmer swims in water, but also when an airplane flies through the air, when a baseball flies through the air, and even when raindrops fall.
Conversely, the same applies when an object is stationary and a fluid flows. The wind you feel when you turn on a fan is the same as the wind you feel when riding a motorcycle. Therefore, fluid mechanics also analyses what happens when wind blows through gaps in buildings or when river water flows around bridge pillars. The same applies even if the object changes slightly. The same resistance occurs between objects and fluids when water flows through a water pipe or when wind blows into a tunnel. Although a little more complicated, resistance also occurs when blood flows through blood vessels. This is also analysed in the same field. Fluid mechanics is a field of study that analyses all phenomena that occur between fluids and objects.
So how does fluid mechanics analyse these phenomena? There are two main methods, which are divided into two fields: experimental fluid mechanics and computational fluid mechanics. These two methods are used to measure resistance and observe various other phenomena.
Experimental fluid mechanics is, as the name suggests, the analysis of phenomena between fluids and objects through experiments.
Using the example of swimsuits again, we can observe or measure what happens when mannequins wearing different swimsuits move in water. If the goal is to reduce resistance, we can select the swimsuit made of the material with the least resistance through such experiments. Of course, it would be foolish to make swimsuits of all materials and dress expensive mannequins in them, so it is also very important to find a way to conduct experiments at a lower cost and with less effort.
Computational fluid dynamics is the analysis of fluid dynamics using computers. It is a method of calculating the dynamic properties of objects and fluids by converting them into formulas and numbers. However, its use is still limited because there are significant differences between the results of experiments and the results of calculations when analysing complex phenomena or when the properties of objects are not well understood. However, with the advancement of computer performance, its applications are expanding. Despite these technical limitations, analysing phenomena using computational fluid dynamics has the advantage of significantly reducing costs compared to conducting experiments.
Our surroundings are full of fluids, and we live in fluids, so in fact, all moving objects are subject to fluid dynamics analysis. Of course, because fluids move, even objects that are stationary are subject to analysis in this case. Therefore, there are many phenomena to analyse in the world as seen by engineers who specialise in fluid dynamics.
There are many subjects to analyse, but by selecting one of them and studying it thoroughly, it is possible to create new value.
It can provide a foundation for technologies that can be applied to other technologies, and it can also be used by companies to make money. When fluid mechanics analysis was applied to sports, it led to such amazing performance improvements, such as the ‘Laser Racer’ swimsuit, that it was eventually banned! In the automotive industry, reducing the drag of a car saves fuel! This means that the company can make more profit.
Of course, fluid mechanics is not only necessary for creating value. How do football players kick banana kicks? How do baseball players throw curveballs? Why is shark skin rough? When viewed through the lens of fluid mechanics, the world is full of interesting and curious things. Fluid mechanics is the process of studying and analysing these curiosities to find answers.
