Automotive Aerodynamics

You can see here there is more red on the front faces of the car. This is because the diameter of the dome on the front face of the car is flatter, so the air is hitting a flatter surface, creating more drag and slowing the car down. The drag coefficients will be shown below on the graphs.

There is still red on the faces of the cars, but there is significantly less than the car on the right. This is because the dome is a sharper shape, so less flat surface is hitting the air and creating less drag.

This car is driving on two thin wheels, which means that there is less air hitting against the surface creating less drag. 

This car is driving on a pair of thin wheels and a pair of thick wheels, where you can see there is more red area on the thick wheels. This means the thick wheels are creating more drags.