Over the years there, you might have seen many changes in the Car design due to space requirements, legal restriction, best fuel economy and Power. Aerodynamics is an integral part of the car design process of both regular road cars as well as high end performance and race car design.
A moving car faces Air Resistance, gradient resistance and rolling resistance. Air resistance is resistance offered by the air to the moving object. It depends on several factors like shape, Size and Speed. Air resistance can be divided into two separate forces: drag and lift. The design of the vehicle should help to overcome these resistances. Engineers find many ways to minimize drag and lift force. Surrounding air always interacts with the car whether you are driving at slow speed or at high speed on highway or race track. At high speed you can quickly feel air resistance and also how car design is closely connected to handling at high speed. Airflow around the car is channelled; by using a rear spoiler, front air splitter that decreases lift. Lower the drag coefficient means better car performance. Wind tunnels are used to test the aerodynamics of the car.
Aerodynamics is the study of interaction between air and solid bodies moving through it. It has a tremendous effect on the way solid body cuts through walls of air. It defines car handling, performance and fuel economy. Aerodynamics evolved out of a combination of Physics, math and fluid dynamics.
Let’s understand how the aerodynamics component of the car helps to limit the air resistance, supply high pressure air to the engine for maximum output as well as helps in faster cooling of car brakes, intercooler and radiator.
Front Splitters
Many sports cars are low and close to the ground. There is a reason for it. Aerodynamic drag gets reduced if the frontal area of the car is low. When a car moves at high speed; air generates a high pressure zone and pushes the car backwards. The front splitter is placed below air dams. Front splitters are flat plates at front of the car that ensure the wind chips up and therefore keep the front of the car pushing downwards. It captures high pressure air and fragments it. This helps to generate downforce on the car.
Spoiler
Spoiler is also known as wings. Spoilers are placed on the rear of the car. The primary purpose of a car spoiler is to spoil unfavourable air movement. It’s an aerodynamic device, most often fitted to performance cars or sports cars. Spoiler pushes the car downwards. Spoiler is positioned high enough so they free oncoming air that does not create the turbulent air that is generated due to the geometry of the car. Air streamlines travel above the car while some air streamlines travel below the car body. Streamlines above and beneath the car should form a laminar throughout the length of the car but in real life this doesn’t happen. In real life; the front Airflow has a laminar but the airflow turns into turbulence due to sudden decrease in rear of car shape where air pressure drops. A spoiler helps to maintain laminar airflow. Spoiler also reduces drag that helps in good mileage. Spoiler helps to reduce vehicle lift which results in better traction control as well as better handling.
Scoops
Scoop is placed above the bonnet. Scoop forces airflow into the engine bay of the car if the car has a top mounted intercooler or radiator. It helps in faster cooling and better efficiency. Scoop also creates aerodynamic drag as it forces more air in the engine bay hence it is not a good choice to reduce drag as airflow comes from both front air dams as well as scoops.
Hood Vents
Some cars feature hood vents. When air comes inside from front air dams; it hits the radiator and goes through the radiator and then flows out through hood vents. Hot air flows out from the top. This helps improve downforce as air turbulence is not created since some air particles stagnate on the front of the car.
Front wheels of the car rotates at high velocity. That creates a high pressure zone. If that high pressure air is ventilated then that air colloids with incoming air and create further downforce.
Ducts help to keep brakes and engine components cool.
Side Skirts
Normally air slips underneath the car as the car gains speed. This wind creates drag and immensely affects car handling. Side Skirts restrict airflow entering underneath the car from sides which disrupts low pressure front. Side Skirts also improve car aesthetics.
Air Curtain
Air curtains are small aerodynamic devices. Air flows through the air curtain then reaches the front wheel of the car and then flows out from vents at the back of the fender. It also releases turbulent air that exists between the back of the front wheel and fender walls. This turbulent air may create drag. Air curtains are drag resistance devices. You may find them in normal road cars like Hyundai i20 N. It helps to make the vehicle more aerodynamically efficient as it directs air flow across the wheel to reduce wind turbulence.
Diffuser
Diffuser is placed at the bottom of the car. Diffuser spreads airflow below the car and airflow releases beneath the car in a controlled way and this improves transition of airflow underneath the car. This can really accelerate air beneath the car and create a low pressure zone below the car. It influences the car’s handling for example; it influences understeer or oversteer of the car.
Canards
Canards are also known as dive planes. It’s very important to have downforce in mid-engine cars. They help in forward balance of the car. Canards are actually small and make a small amount of downforce but canards help to create low pressure air underneath the car as the front splitter creates a high pressure region near the bumper. Hence proximity of canards and splitter is very important. You might have seen canards in GT race cars.
Air Dam
Air dam is an important aerodynamic part of your vehicle. Air dam is usually found at the bottom of the front grill of the car nose. Air dam ensures high pressure air should reach the engine. It directs airflow around the car instead of under it. The car will be more stable with an air dam when you drive at high speed. Air dam keeps the car nose pointed at the ground and keep it steady. Air Dam helps improve airflow and decrease drag. It adds great aesthetic appeal to cars.