Andrey Yurlov Though the term "aerodynamics" is most commonly associated with airplanes and the overall science of flight, in fact, its application is much broader. Simply put, aerodynamics is the study of airflow and its principles, and applied aerodynamics is the science of improving manmade objects such as airplanes and automobiles in light of those principles. Concept All physical objects on Earth are subject to gravity, but gravity is not the only force that tends to keep them pressed to the ground.
Above slow speeds, the air flow around and through a vehicle begins to have a more pronounced effect on the acceleration, top speed, fuel efficiency and handling. Therefore, to build the best possible car we need to understand and optimize how the air flows around and through the body, its openings and its aerodynamic devices.
Aerodynamic Principles Drag No matter how slowly a car is going, it takes some energy to move the car through the air. This energy is used to overcome a force called Drag. Drag, in vehicle aerodynamics, is comprised primarily of three forces: Frontal pressure, or the effect created by a vehicle body pushing air out of the way.
Rear vacuum, or the effect created by air not being able to fill the hole left by the vehicle body. Boundary layer, or the effect of friction created by slow moving air at the surface of the vehicle body.
Between these three forces, we can describe most of the interactions of the airflow with a vehicle body.
Frontal Pressure Frontal pressure is caused by the air attempting to flow around the front of the vehicle as shown in diagram D1 below. Frontal Pressure is a form of drag where the vehicle must push air molecules out of the way as it travels through the air.
As millions of air molecules approach the front of the car, they begin to compress, and in doing so raise the air pressure in front of the car. At the same time, the air molecules travelling along the sides of the car are at atmospheric pressure, a lower pressure compared to the molecules at the front of the car.
Just like an air tank, if the valve to the lower pressure atmosphere outside the tank is opened, the air molecules will naturally flow to the lower pressure area, eventually equalizing the pressure inside and outside the tank. The same rules apply to any vehicle. The compressed molecules of air naturally seek a way out of the high pressure zone in front of the vehicle, and they find it around the sides, top and bottom of the vehicle as demonstrated in diagram D1.
As it drives down a road, the blocky sedan shape of the car creates a hole in the air. The air rushes around the body as described above.
These empty areas are the result of the air molecules not being able to fill the hole as quickly as the car can make it. The air molecules attempt to fill in to this area, but the car is always one step ahead, and as a result, a continuous vacuum sucks in the opposite direction of the car.
Rear Vacuum Also known as flow detachment is another form of drag where the air the vehicle is passing through cannot fill the space of the hole left behind by the vehicle, leading to what amounts to a vacuum. This inability to fill the hole left by the car is technically called Flow detachment.
In fact, the drag increase with the square of the vehicle speed, so more and more horsepower is needed to push a vehicle through the air as its speed rises. Therefore, when a vehicle reaches high speeds it becomes important to design the car to limit areas of flow detachment.
If you have witnessed the Le Mans race cars, you will have seen how the tails of these cars tend to extend well back of the rear wheels, and narrow when viewed from the side or top. The force created by the rear vacuum exceeds that created by frontal pressure, so there is very good reason to minimize the scale of the vacuum created at the rear of the vehicle.
Turbulence is created by the detachment of an air flow from the vehicle.The concept of a boundary layer is important in many problems in aerodynamics.
The viscosity and fluid friction in the air is approximated as being significant only in this thin layer. The viscosity and fluid friction in the air is approximated as being significant only in this thin layer.
The importance of aerodynamics to a modern Formula 1 racing car are quantified and illustrated through the design procedure of the cockpit models investigated in this study. This is one of five individual studies carried out on different aerodynamic components of a Formula 1 racing vehicle by the Cranfield University Formula 1 Team.
(Race Car Aerodynamics, Designing for Speed – Joseph Katz) Drag is the resultant of aerodynamic forces that acts in the longitudinal axis of the car, opposing its movement.
This is a crucial element of aerodynamics study, and it is of primary concern in road cars aerodynamic design. Leonardo da Vinci considers the aerodynamics of flight and sketches the detailed anatomy of bird wings in his notebooks.
He notes the importance of air resistance (drag) as a force that slows down moving objects and figures out the equation of continuity by watching rivers flow.
Car aerodynamics. As the cost of petrol rises, As cars have become faster over the years, their aerodynamic efficiency has become more crucial because the amount of power needed to propel a car at high speed rises with the cube of the speed.
An example of this is the faired-in k streamlined) front wheels of Ford's concept car, the . Shop For Cars New Cars for Sale Build and Price Get a Free Quote. Connect Magazine Digital Edition Give a Gift Newsletter. Backfires. New Cars. Acura The Greatest Concept Cars of the s.