Glossary

1. Aerodynamics: The study of the motion of gas on objects and the forces created.
2. Airflow: The movement of air around the chassis of the race car.
3. Bernoulli Effect: states that the pressure of a fluid (liguid or gas), decreases as the fluid (liquid or gas), flows faster.
4. 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.
5. Cd: Drag coefficient or coefficient of drag. It is determined by the shape and smoothness of shape of the object. In this case the car.
6. Chassis: Refers to all mechanical parts of the car attached to the structural frame.
7. 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. Here are some examples of CFD data sets.
8. 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.
9. Drag: Force acting on an object in motion through a fluid (in this case air) in an oppposite direction to the objects (chassis) motion, produced by friction.
10. F-1 Race Car: Formula One race car. A different type of race car racing under different rules and regulations. It weights 30% less than an Indy Car and has a flat bottom. Its physical appearance is very similar to that of an Indy Car. The F-1 race car in action has a distinctive high pitch sound, particularly the Ferrari V-12.
11. 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.
12. Laminar: Laminar flow means the fluid is moving in smooth layers around the object. Air flow becomes turbulent moving from the front to the rear of the car, forced around obstructions such as mirrors, helmets, and rollbars.
13. Lift: The upward reaction of an aircraft to the flow of air 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.
14. Monocoque: A Body structure that derives its strength and rigidity from unitized construction, rather than a framework of thick members.
15. Telemetry: An electronic device which 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.
16. 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.
17. Turning Vane: Deflectors located between the front wheels and sidepods 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 F-1 race cars, and on some Indy Cars.
18. 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.
19. 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.
20. Visualization: Complex analysis tool that presents CFD data as an image. The image can exhibit surface pressure contours. This example shows fluid flow around complex geometries, using the Nordic ski jumper as the model.
21. Vortex: When a fluid rotates around its own center, it is called a vortex. Turbulent flow is made up of many little vortices.
22. 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. The National Full-Scale Aerodynamic Complex located at Ames Research is the largest wind tunnel in the world. Included in this facility is the Unitary Plan Facility, the most heavily used wind tunnel in all of NASA. The Glenn L. Martin Wind Tunnel located at the University of Maryland, offers a broad range of testing applications from conventional aircraft to ground vehicles. Antoher type of "wind tunnel" is the computer generated Virtual Windtunnel. This explores the flowfield around a dataset of the space shuttle.

Author:Bryan Yager, Ralston Middle School, Belmont, CA (12/94)