AERODYNAMIC DRAG

The vehicle body causes a certain amount of frictional force while moving through air. The major components of aerodynamic drag are skin friction and shape drag.

• SKIN FRICTION

When the vehicle moves forward, it disrupts the layers of air moving around the vehicle. The layer of air closest to the surface collides with it. This slows down the air particles closer to the surface. Slowed air particles interact with the nearby air layers and produce skin friction. This only significant at a distance that ranges from millimeters from the surface of the vehicle. Consequently, the difference in speed between the air molecules near the surface contributes to skin friction. It can be reduced by smoothening the body of the vehicle.

• SHAPE DRAG

This is caused by the shape of the vehicle. When the vehicle moves forward it pushes the air in front of it. However, the air cannot move immediately. Thus a high pressure is formed in front of the vehicle. This pressure opposes the forward motion of the vehicle. In addition to it, the air cannot fill the space instantly left by the forward motion of the vehicle. This creates a low-pressure region at the backside of the vehicle. Low-pressure regions drag back the vehicle motion. The two pressure zones are depicted in the figure above. Both zones oppose the forward motion of the vehicle. 

 Written by

EV MAN