Have you ever wondered why eagles streamline their bodies before diving toward prey, or why fish are shaped the way they are? What would have happened if they were entirely different shapes? These fascinating adaptations aren’t just vital for survival but are also great inspirations to design automobiles. They are all about aerodynamic resistance, in other words, drag. This article will explore drag and how the outer shapes of automobiles, influenced by such creatures as birds and fish, are designed to overcome drag.

Like all physical matter, air has mass and density. As a car moves on the road, it encounters these air particles trying to slow down the vehicle. The car’s contact with these air particles creates a resistive force called drag while moving.

Think about Newton's 3rd Law, which states ‘For every action in nature there is an equal and opposite reaction.’ When you push a wall with your finger, the wall pushes back with an equal amount of force. Now, imagine a fish swimming in the sea. As it swims, the fish exerts force on water particles, which in turn exert an equal force back to the fish. The same logic applies to drag in automobiles. The car collides with billions of air particles simultaneously, each exerting the same amount of force back onto the automobile. That is the reason why drag happens in nature.

Aerodynamic resistance, or drag, is one of the main concepts in automobile engineering. It affects a car’s speed, fuel efficiency, and stability. Understanding drag is significant to understand why modern cars have evolved into smooth shapes throughout the past and present.

Drag is directly proportional to air density, the square of the vehicle velocity, drag coefficient, and frontal area.

The car encounters more air particles per unit of time at higher speeds, increasing the drag. Doubling the car’s speed causes drag to quadruple. As a result, more fuel or energy is required to overcome drag, making it especially important to reduce it in electric cars to extend their range.

Drag is also related to the density of the particles in the air. Air density varies with factors like altitude and temperature, though these changes are typically minor and often negligible.

The main point to overcome drag is the car's ability to get through these particles as smoothly as possible. A car’s aerodynamic shape plays a crucial role in reducing drag, which is why engineers design streamlined bodies with smooth surfaces and spoilers. Features like rounded edges and sloped windshields are some examples of helping to go through the air particles.

As seen from the table, the drag coefficient varies depending on the outer shapes of the object. These results were derived after numerous experiments were conducted. We asked what would happen if fish and eagles had different shapes. Well, more energy and muscle power would be consumed since the drag coefficient of these animals would be much higher. As a result, streamlined shapes, like those of fish and eagles, are considered optimal to minimize drag.

Aerodynamic Resistance Visualization on Porsche Taycan

Measured Drag Coefficients

To sum up, drag is an unavoidable force affecting every object, from diving eagles to cars speeding along the highway. Just as nature has proved the magnificent art of streamlining for survival, engineers take inspiration from these designs to create more efficient and stylish automobiles. Aerodynamics will continue to play a critical role in shaping the design of automobiles in the future to achieve features like optimized fuel consumption, extended range, and improved speed. Moreover, mastering aerodynamics not only allows us to improve the automobile but also drives us closer to a more sustainable future.

AERODYNAMIC RESISTANCE

Examples of great streamlined designs include the Porsche Taycan and Tesla Model S, both investing in aerodynamic shapes to minimize drag and enhance the visual appearance.

Eren Erden