Aerodynamics Buyers GuideThe wind beneath our wingsMore aftermarket aerodynamics from the world's best design housesConversations and theories about aerodynamics abound in the automotive industry, and if you wanted to throw puns around, you could say it is a lot of hot air passing over stiff resistance. Does a car go fast enough to warrant a full body kit? Is a spoiler or airdam necessary on american highways? Will i affect my car's performance enough to offset the cost of the variety of packages on the market today? These questions can be argued until your car becomes an antique, but the only solid answer with any kernel of truth that everyone can agree on is that most aerodynamic-themed accessories make your car look cool. Whether they improve handling, fuel economy, or 60-foot times are issues best left to physicists, engineers, and bench racers (unless, of course, you have the time slips to prove it).
Glossary of termsAerodynamics: the study of the motion of gas on objects and the Forces created.
Airflow: the movement of air around the chassis of the car.
Bernoulli effect: states that the pressure of a fluid (liquid or gas) decreases as the fluid (liquid or gas) flows faster.
Carbon fiber: carbon-based composite material that is strong in tension but reasonably flexible. It can be bound in a matrix of plastic resin by heat, vacuum, or pressure. It is strong, light, and expensive.
Cd: drag coefficient, or coefficient of drag. It is determined by the shape and smoothness of the object, in this case, the car.
Chassis: refers to all mechanical parts of the car attached to the Structural frame.
Computational fluid dynamics (cfd): equations that are known are programmed into computers. The computers provide solutions to the problem of external airflow over vehicle shapes. The body of the configuration and the space surrounding it are represented by clusters of points, lines, and surfaces; equations are solved at these points. Cfd is divided into three steps: grid generation, numerical simulation, and post-process analysis.
Downforce: a vertical force directed downward, produced by airflow around an object. Downforce is generated from the front and rear wings and the venturi tunnels on a ground effect car.
Drag: force acting on an object in motion through a fluid (in this case, air) in a direction opposite to the object's or chassis' motion, produced by friction.
Ground effects: downforce created by an a low pressure area between the underbody and the ground, and downforce created by the front And rear wings.
Laminar: laminar flow means the fluid is moving in smooth layers around the object. Airflow becomes turbulent moving from the front to the rear of the car, forced around obstructions such as mirrors, helmets, and roll bars.
Lift: the upward reaction of an object to the flow of air forced over the shape of the wing (airfoil). The front and rear wings of ground effect cars are shaped like inverted wings to create downforce or negative lift.
Monocoque: a body structure that derives its strength and rigidity from unitized construction, rather than a framework of thick members.
Telemetry: an electronic device that transmits specific data (measurements) to a remote site. It electronically records performance of engine and actuation of controls by the driver. The data is then used as a foundation for determining car setup.
Turbulent: turbulent airflow is when the fluid streamlines break into eddies and complex changing patterns. This can cause unstable forces on an object. As the airflow moves from the front of the car to the rear it becomes turbulent.
Turning vane: deflectors located between the front wheels and side pods to direct turbulent flow away from the tunnels. This eliminates a source of turbulent air to the tunnels. Cleaner air to the tunnels creates more downforce-currently seen on most f1 racecars, and on some indy cars.
Venturi: a narrow tunnel under the side pod, shaped like an inverted wing. As air enters and is forced through the narrow center, its speed increases, creating a low pressure area between the bottom of the car and the track. This creates a suction effect which holds the car to the track.
Venturi effect: fluid speed increases when the fluid is forced through a narrow or restricted area. The increased speed results in a reduction in pressure. The underbody venturi is shaped to create a low pressure area between the road and chassis, which creates downforce.
Vortex: when a fluid rotates around its own center, it is called a vortex. Turbulent flow is made up of many little vortices.
Wind tunnel: a tube-like structure where wind is produced, usually by a large fan, to flow over the test object. The object is connected to instruments that measure and record aerodynamic forces that act upon it.