Car aerodynamics works on the law of Physics based on the Bernoulli Effect. According to this law, if a fluid, gas or liquid, moves around an object at different speeds, the slower moving fluid exerts more pressure on the object forcing it to move towards the faster moving fluid.
This principle enables the aircraft to fly and the concept of car aerodynamics was imbibed from aircraft. So, similar to the pressure and movement of the aircraft, cars aerodynamics also works in accordance to Bernoulli Effect. The only difference between the aircraft and the car is the placement of the wings and action of air.
In case of an airplane, the wings are shaped upward because air moving over the wings moves faster than the one below the wings. The slower moving air below the wings exerts more pressure and pushes the aircraft upwards or creates a lift for a better flight. Similarly, in case of a car the chassis is shaped and designed in such a way that controls the movement of air to have improved and better acceleration.
When talking about cars, they need a downforce instead of lift. This is because they need more pressure over the hood so that the car acquires better stability of road even at higher speed. This opposite force is delivered by placing the wing upside down. The chassis is shaped similar to an upside down airfoil to create a negative lift and increase the traction between car tyres and the road.
As the air is slower over the surface it generates more pressure and puts extra weight on the car for maintaining high cornering speeds and increasing traction. For this, the car body
structure has to be defined in a manner to support the movement of air as well as the force it applies on the moving car.
The entire focus is laid on aerodynamic design and improvements that is mainly concentrated in three specified areas of a car, front wing assembly, rear wing assembly, and the chassis.
Front Wing Assembly
Front wing assembly, constructed of carbon fiber, is the first part of the car to come in contact with the flowing air. The wing should be designed in such a way that it creates maximum downforce. The efficiency of the wing depends on the aspect ratio and angle of attack.
Aspect ratio is the ratio of length to width of the car. The size of the wing plays a vital role in determining its efficiency and improving aerodynamics. If the aspect ratio is higher, less air resistance will be created, further generating more downforce.
Angle of attack means the angle or tilt of the wing where the moving air makes a direct contact. This angle should be greater in order to generate more downforce. This also helps improve downforce/drag coefficient. Drag is the force required by a car to pull and move against the air resistance.
Rear Wing Assembly
Rear wing assembly is also composed of carbon fiber and is attached to the transmission housing. As the air moves from the front to rear end it becomes more turbulent as it is highly influenced by the front wing, rearview mirrors, and front car wheels. All these come as obstructions in the path of air flow that further creates an imbalance of the moving car.
The rear wing assembly needs to be aerodynamically more efficient than the front wing to balance the car at high speeds. In case of rear wings also, aspect ratio and angle of attack plays a vital role to achieve greater downforce and minimize accompanying drag.
The configuration of the chassis also plays a vital role in improving car aerodynamics. Downforce generated by front and rear wing assembly allow maximum cornering speeds. To accomplish this car roof should be designed to slice through the air whereas the underbody should be shaped to create an area of low pressure between the underbody of the car and the road.
Formula One car designers design skirts on the cars to minimize lateral airflow under the car. It was one of the best design specifications to improve aerodynamics but was later ignored because of safety reasons. At present, flat bottom chassis has also become a trend in the car industry.
, engineers, and manufacturers are on their hunt for better and more efficient design specifications to improve aerodynamics. This hunt is attributed to the increasing demand of higher speed, greater acceleration, and improved fuel-efficiency
. Sleek body structure, reclining windshields, and lower ground clearance are some of the specifications hunted till date. With this the search is on until the perfect aerodynamic car body structure is not unveiled.