Aerodynamics is the study of motion of gas on objects and the forces created. The same principles that let air planes fly is used in racing cars. The difference is the wing is mounted upside down to keep down force on the car instead of lift. Downforce is vertical force directed down made by airflow around an object. Down force is generated from front and rear wings and the venturi tunnels on ground effects cars. Lift is the upward reaction of a plane to the air forced over the wing. The Bernoulli Effect means if fluid (gas or liquid) flows around an object at different speeds, the slower moving fluids will exert more pressure than the ones going faster. The wing on a plane is designed so that the air moving over top the wing moves faster than the air below the wing. This is because the air pressure under the wing is greater than over the wing and this produces lift which lets the plane fly. The shape of an Indy car has the same principles. The shape of the car is designed like an upside down airfoil or wing. The air that moves underneath the car moves faster than the air over the car. With the design like this it puts down force or negative lift on the car. Wings are placed at the front and rear of the car to create even more down force. Down force is necessary in maintaining high speeds through the corners and it forces the car to the track for traction. An Indy ground effect racecar can reach speeds in excess of 230 mph using down force. The under body of the car do to its inverted wing shape creates suction which plants the car on the ground this allows high cornering speed. .
Aerodynamics is in race cars is stressed more than ever. Most teams use track testing and wind tunnels. A wind tunnel is a tube like structure where wind is produced usually by a large fan to flow over the object they are testing.