Question

Automobiles and trucks are often designed with a tapered ("aerodynamic") rather than a blunt front surface. Why is this? What does the tapered front accomplish? How important is it?

Answer 1

We normally observe that for any moving auto mobile, the major force that it has to overcome is air resistance. Therefore in order for the air to bend around the surface of the automobile so that it can take the least distance of the path, the shape of the automobile is designed with tapered ("aerodynamic") model. The tapering is complemented by providing tilts and curves at appropriate locations wherever there seems to be more air friction. The air in such spots bounce off the surface.

Such a tapered design also helps to reduce the consumption of gasolene fuel at higher speeds. Fuel consumption due to aerodynamic drag consumes more than half of the automobile's energy. Reducing the aerodynamic drag provides an inexpensive solution to improve fuel efficiency. The daily operational cost of the automobile will also be reduced.

There are two components of aerodynamic drag such as Pressure drag and skin friction drag. The pressure drag contributes for more than 80% of the total drag. The vehicle geometry plays an important role to overcome such pressure drag. Altering the shape of the vehicle to obtain aerodynamic design is called streamlining. The share of pressure forces in the total drag force is small. Drag is mainly caused by shear stresses.

When we observe the front face of the automobile, the drag coefficient, which is a measure of performance is highest. This is caused by the overpressure on the front face. The overpressure can be reduced by accelerating the air flow. This can be accomplished by providing a tapered front. The reasoning as mentioned earlier helps us to understand that tapered (aerodynamic) design plays a very important role.