AERODYNAMICS OF ROAD VEHICLES

  Introduction Road vehicles are bluff bodies with extremely complex geometry. Engine compartment, wheels, mirrors and other external and internal attachments and recessed cavities creates geometrical and fluid mechanical complexity. The flow over a vehicle is fully three-dimensional. Boundary layers are turbulent. Flow separation is common and may be followed by reattachment. Large turbulent wakes are formed at the rear and in many cases contain longitudinal trailing vortices. Drag in road vehicle is mainly due to pressure drag. In aircraft, the drag is mainly due to the friction drag. The avoidance of separation or its control is the main objectives of vehicle aerodynamics. With regard to their geometry, road vehicles comprise a large variety of configurations. Passenger cars, vans, and buses are closed, single bodies. Trucks and race cars can be of more than one body. Motorcycles and some race cars have open driver compartments. With the race car being the only exception, the sh...