ABSTRACT
The defining element of automotive aerodynamics is drag, defined formally as the resistive force to the flow of an object through a fluid. In this case, the fluid is air and the object is a car. So, drag is the force resulting from airflow that resists the forward movement of the car. The most significant form of drag is defined by the shape of the car, not surface friction. Though, this does not mean that we can ignore skin friction; as we’ll see, it interacts with the vehicle’s other characteristics to define overall aerodynamic performance. The high pressure at the front of the car is the largest single component of form drag. A front air dam can help place more high-pressure airflow over the top of the car, and by slowing the airflow under the body it can reduce drag caused by the undercarriage.
