CFD in Formula One

If there is a racing series which can be considered the pinnacle of motorsport, that is, without any doubt, Formula One. As opposed to the view of those who do not watch auto racing very often, this sport happens to be much more than a handful of cars racing around a circuit - it is the ultimate racing league, in which the very best drivers compete in state-of-the-art machines whose only design costs hundreds of millions of dollars each year. A loss of a mere second per lap is regarded as a huge advantage.

CFD design of an open-wheel racing car

In order to achieve maximum performance, all the parts of Formula One cars are thoroughly designed and tested, and then they have their performance evaluated. Besides track testing, there are two tools which can be used to study how any modification in the chassis -along with the tyres, the part in the car with the biggest impact on its performance- will affect a car's aerodynamic profile. These are wind-tunnel testing and computational fluid dynamics.

Computational fluid dynamic -CFD for short- is the study of the forces which affect fluids -mainly air, but also liquids like water- through computer algorithms and numerical methods. This group of techniques has only been used in Formula One since a few years ago, but it had already been pioneered in the 1980s. CFD allows engineers to develop aerodynamic components such as wings, deflectors, engine covers and diffusers and measure their effect in a car's behaviour without the need of undergoing the expensive process of manufacturing components which are to be tested in a wind tunnel, and that often are thrown away as scrap because they do not work as well as desired.

A lower formula car in a wind tunnel

The main advantage of CFD over traditional wind-tunnel testing is its relatively low cost. Although CFD relies on powerful supercomputers, the cost of these is nowhere near the exaggerated amounts of money which teams often spend in building scaled-down models of their cars that will be tested in wind tunnels. As a result, a team's budget can be notably benefited from the usage of CFD design instead. However, it should also be noted that this technology is very recent and, as such, it is not completely accurate yet, which means that most teams usually run a combination of CFD, wind-tunnel testing and, to a lesser extent, track testing, as this last one is forbidden while the Championship is going on, and only takes place in the gap between seasons.

The benefits of CFD seem to have convinced Virgin's Richard Branson to run his own team, Virgin Racing, with the lowest budget of all teams in the 2010 season -a modest $40 million-, and which will rely only on this innovative technique to design their car. However, their radical approach has been slammed by Williams' head of design Adrian Newey, who recently stated that the only usage of CFD was not a viable tool to design a car, but that wind-tunnel testing was completely necessary as well. However, the British engineer was quick to add that, should Virgin show up with a powerful contender, he would withdraw his previous saying.

Three drivers (left to right: Lucas di Grassi, Timo Glock and Luiz Razia) stand next to the VR-01, the first Formula One car ever designed by using only CFD techniques

In any case, it should be remembered that CFD is not at all the only application which computers have on Formula One. Instead, these are used for almost everything. Engineers can receive a car's telemetry on their laptops and simulate how a change in the car's configuration would have an impact on a driver's lap times, design innovative systems to improve an engine's fuel consumption or power, or run benchmarks about any modification in the car would affect its reliability.

To sum up, computational fluid dynamics aren't only a valuable set of tools which can be used in Formula One to design cars, but also a way to reduce costs dramatically. Is CFD the future of car design, and will it make wind-tunnel testing finally disappear? Only time will tell, but, given its expansion in Formula One after just a decade, it cannot be argued that CFD has come to stay for many years.