A few years after the automotive industry emerged, as early as the 1920s. By 1950s German and British automotive engineers became more and more interested in the effects of drag over the high performance vehicles. Ten years later, they realised that the sound levels increase as the travel speed increased too.
The automotive aerodynamics studies the flow of air around road vehicles. Its main purpose is to reduce the drag and the noise created by the wind, thus minimizing the emission of noise, and preventing the instability of vehicles at higher speeds.
In the field of racing vehicles, it plays an important role, especially to produce downforce, that helps traction and the abilities to corner. The downforce pressure is the characteristic which helps a vehicle travel faster, while adhering to the track and road surface. It is intimately related to the drag coefficient. In order to produce a good drag, a vehicle must have a good downforce, and vice versa.
Good aerodynamic engineers and designers will create bodyshapes with integred wheel arches and light to the overall shape, in order to reduce drag. Usually, the air flowing around a vehicle is streamlined, crossing the windshield streamlined and creating some sort of vortices at the rear of the vehicle, a few centimetres behind it. The challenge of these professionals is to reduce as much as possible these vortices at the back of the vehicle, as they reduce the speed of the vehicle and increase drag. Some modern vehicles are inspired by race cars, which enable air to enter the nozzle, and eject through the floor or through the wheel arches. This has a double purpose: to cool the engine or other components and to achieve stability down the road, especially while cornering.
Any element of the car exterior can influence the air flow: the roof rails, antenna, mirrors or even the door handles.