AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS AERODYNAMICS Written by Nathan Lityo Design and edit by Rebecca Sopacua
Spoilers, diffusers, and splitters are just some of the many things of how a car takes advantage of aerodynamics. When a car is speeding through the highway, not only is there friction between the ground and the wheels so the car grips to the ground, but also air resistance which slows down cars as they go faster. Aerodynamics slows down the car because it is almost like swimming in endless air ocean that slows it down. Engineers resolve this problem by making cars not boxy shaped, instead making it more streamlined, so that the car would slice through the air but not push it out resulting it to achieve higher efficiency and speed.
If we take a look at a wind tunnel, boxy shapes will leave a small twirl of air in the back as well as in the front. This air is then called turbulence, while the streamline air is called laminar. When there is more turbulent air around the shape-- meaning that the drag coefficient is higher than the shape, it has less turbulent air around it. A great example of a low drag shape is a teardrop. It has a drag coefficient of 0.05, due to the curved shape it has in the first part. In the end, it has a slope that guides the air, creating a Coanda effect this slope that leaves a small gap for any air to create turbulent air flow.
TURBULENT AIR CREATES DRAG IN THE BACK OF A BOXY CAR Written by Nathan Lityo Design and edit by Rebecca Sopacua
The designers of this car decided to replicate the shape of a teardrop, so that it has barely any drag and barely any turbulence in the back. As you can see closely, the flow of the smoke is still in laminar flow until the back of the car.
In flying applications, just being aerodynamic isn't enough. The wings of planes has a flat bottom and a curved top, like half of a teardrop shape. Low pressure on the top of the wing and high pressure on the bottom of the wing means that there is a pressure differential. This creates a lift. The pressure is different due to the fact that the air needs to go through the same time, one of which has a longer distance to go to, which has greater speed. The lift is what brings the airplane up to the skies. However, in race car applications, the opposite is needed. Instead of a positive lift, a negative lift is needed. So in reverse, the top side is flat, while the bottom is shaped like a half teardrop. In theory, this should apply low pressure under and high pressure on top, creating a negative lift or downforce. Downforce is mostly only required in high performance cars as it aims to have a maximum amount of grip without putting weight to the car, otherwise, the mass will increase if a wing is added in the back of a car and a diffuser in the front, which in result, will push the car down. Even though wings and spoilers makes more drag, it’s a good trade of grip.
THE WING IN THE BACK AND THE FRONT OF THE CAR, WHERE THERE IS A SPLITTER, HAS TURBULENT AIR, CREATING MORE DRAG INSTEAD OF DOWNFORCE Written by Nathan Lityo Design and edit by Rebecca Sopacua