Mechanics of the DRS System

First, we have to understand what a multi-element wing on a formula one car is. Normally, a formula one car’s rear wing would at least have an angle of attack which is tilted upwards, meaning that at the rear tip of the wing, flow separation always exists, causing stalling as the angle of attack increases that can increase drag and decrease downforce. In order to minimize the flow separation, the flow across this region must have an increased energy level to stick it onto the boundary, and this amount of energy cannot be achieved solely by the bottom part of the incoming airflow. Now thinking in a more general perspective, the upper airflow passing above the flaps isn’t disturbed, while maintaining high energy level as it is constantly pressurizing the top of the flaps, so if we construct a chamber to connect two different regions, this can energize latter part of the flow to stay attached to the boundary layer and increase downforce significantly. However, these sharp edges along the chamber are not stream-lined, so the most aerodynamically efficient manner is to build two layers of flaps called a multi-element wing.

However, due to the fact that increase in downforce can cause induced drag as discussed before, this is not ideal on straights because the straight-line speed of a race car is affected by drag rather than downforce, forming a negative relationship between these two parameters. The solution here is the DRS system, by flattening the gurney flap on the straight, the flow becomes smoother, and the drag decreases dramatically. This is why when you are watching two car battles along straights, the latter car opens the DRS, and its highly likely that they will complete an overtake