Originally Posted by ryannoe
Remember what aerodynamic drag really is... its the amount of force on the vehicle from you accelerating the air in the direction of the vehicle. Drag is dependent on two things: 1. how much air & 2. how fast you accelerate that air forward (in the direction of the vehicle).
Want to REDUCE drag? Reduce the amount of air impacted (smaller frontal profile) or lessen the acceleration of the air (smooth the flow over the length of the vehicle).
**Don't forget you are pushing the air in the front (high hanging fruit), and sucking the air in the back (lower hanging fruit)**
HOW THIS APPLIES:
The lessen the amount of air that you have being pulled forward by the protrusions under the car by reducing the gap between the car and the ground. This will reduce the amount of air available to be accelerated. It will probably have the same acceleration, but less air means less drag.
Other aerodynamicists chime in...
The ph.Ds are going to say that the drag that we're interested in,is caused by flow separation and the static pressure differential between the forward stagnation point and the turbulent wake which it causes.
Hucho will say that the entire premise of streamlining is to reduce or eliminate the wake.
Less air is less drag.Drag varies arithmetically as a function of projected frontal area,all else being equal.If you reduce the Af by 50%,you've just cut drag by 50%.