When we talk about car aerodynamics and how far it has come, the most visible change is the design of modern cars. It’s amazing how small changes in design have transformed the automotive and aviation industry over the last decades. Vehicles these days have a sportier and sleeker look as compared to the boxy exterior popular till the 80s. Based on individual research and studies, vehicle manufacturers design their products to take advantage of vehicle aerodynamics.
The question remains, how aerodynamics help and why has it become such an important ground for research and development in the automotive sector.
What is Car Aerodynamics?
Aerodynamics in general is the study of airflow around a moving object. In our case, the moving object is a car.
Back in the early days, cars used to be slow and the impact of aerodynamics was almost negligible. However, when you add speed to the equation, the interaction between the airflow and exotic cars becomes a lot more important.
In fact, the whole theory of automotive aerodynamics is based on two key interactions, drag and lift.
Drag
Drag is basically the opposite force generated by a car moving across the air. As air is still a medium, a car speeding through the air will face resistance or in other words friction. Hence, the design of the car and speed plays a vital role in drag magnitude.
Drag Formula
D = Cd x A x 0.5ρ x V2
If we break down the drag formula, we can understand exactly what factors influence the drag force.
- Cd = Drag Coefficient of the car – often calculated experimentally
- A = Frontal Area of the car
- ρ = Density of the Air
- V = Velocity of the Car
From the equation, it is evident that the drag coefficient, speed and frontal area of the car are prime factors affecting drag force.
Since the drag force increases with the speed of a car, it becomes an important factor in fast cars, which is nearly every modern car today.
Lift
Lift is usually a problem often associated with racing cars. When you drive a car at high speed, you will often face control problems. This is because of lift or vertical force generated from the ground due to surrounding airflow. This becomes a problem when a car makes a turn and will be prone to get lifted or tipped off due to excessive vertical force.
This is where aerodynamics comes into play. With proper design, a car can be designed to create a downward force to offer more grip and stability on the road turns.
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Now the downside is, the downforce also creates drag, but the trade-off is all in the balance.
Lift Formula
Lift is also calculated just like drag force; instead, it makes use of lift coefficient
L = Cl x A x 0.5ρ x V2
Reason Behind Creation of Drag and Lift Force
To understand the reason why these opposite forces are generated, it all comes down to air pressure.
When a car is moving against air, it creates a high-pressure zone in the front and a low-pressure zone at the rear. The front end of the car blocks the air path thus creating a push force. This phenomenon is also referred to as pressure drag.
In the case of lift force, it is generated due to the difference between air pressure on the top and bottom of the car. Hence, as the car moves faster, the net upward force or lift will increase.
Countering Drag and Lift Forces
We won’t go into details about how certain design changes affect drag and lift forces. In a nutshell, everything is about adjusting air pressure by diverting its direction.
Car aerodynamics are usually more focused on sports cars owing to their high performance and fast speed. However, there are many pros and cons of daily driving a sports car.
Here is how automotive designers tend to reduce the drag and lift coefficient of the car
- Air Dams – Cuts drag force and increases downforce while also allowing air to keep the engine cool
- Drive Plates – Commonly found in race cars to direct air around the sides to generate downforce
- Car Undertray – Improves airflow beneath the car, which reduces overall air pressure and turbulence
- Diffuser – Usually added to race cars to allow a smoother transition of air underneath the car
- Strakes – Placed alongside diffuser so air can move in an orderly fashion
- Side Skirts – Blocks the high pressure from making its way to low pressure area underneath the car thus increasing the downforce
- Spoilers – Creates better airflow, enhances downforce and improves traction
Aerodynamics in cars is essentially about countering resistive forces like drag and reducing lift by increasing downforce. If you are looking to modify your car with spoilers, side skirts and other accessories, you can purchase various new and used car parts for sale in the UAE. However, some knowledge about car aerodynamics will definitely help when customizing your car for speed.
Stay tuned to the UAE’s leading auto blogs for more information on automotive parts, market trends and automotive technology.
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