Side Skirts, Diffusers, and Air Dams | How It Works | Science Garage

Summary

This video script delves into advanced automotive aerodynamics, exploring components like side skirts, diffusers, and vortex generators that enhance downforce and reduce drag. It reviews the function of air dams and canards, then dives into underbody aerodynamics, explaining how undertrays and diffusers utilize the Venturi effect to increase downforce. The script also highlights the innovative Chaparral 2J's use of fans for downforce and the role of vortex generators in maintaining smooth airflow for improved performance.

Takeaways

• 🏎️ Drag is the force of air against a moving car, while lift is the perpendicular force exerted by air on the car.
• 📚 Air dams serve multiple functions, including reducing lift, directing air to radiators, and cooling brakes and other components.
• 💨 Canards, also known as dive planes or plates, are small, flat, wedge-shaped devices that create a small amount of downforce and help balance it between front and rear tires.
• 🚗 A smooth undertray reduces turbulence and drag under the car, enhancing downforce by lowering air pressure underneath the vehicle.
• 🔧 Diffusers, typically at the rear of the car, create a Venturi effect, increasing downforce by accelerating air under the car and reducing pressure.
• 📉 Adding a diffuser can actually reduce drag when combined with a smooth undertray, making it an important way to increase downforce efficiently.
• 🚫 Side skirts block high-pressure air from re-entering under the car, preventing lift and maintaining the downforce achieved by other aerodynamic features.
• 🌀 Vortex generators create vortices that draw fast-moving air into the boundary layer, keeping the airflow attached and generating downforce over the rear wing.
• 🏁 The Chaparral 2J race car used innovative Lexan side skirts and fans to create a vacuum effect, producing significant downforce at both low and high speeds.
• 🛠️ Strakes in the diffuser help keep the airflow orderly, reducing drag and enhancing the effectiveness of downforce generation.
• 🎓 The video script was sponsored by Skillshare, an online learning platform offering classes on various topics, with a promotion for a two-month free trial.

Q & A

What is the primary function of an air dam in a car?

The primary function of an air dam is to direct more air over the top of the car than underneath to reduce lift, divert air to the radiator for cooling, and in some cases, to shoot air directly into intakes, intercoolers, or oil coolers. It also helps to cut down on overall drag.

What are canards and what purpose do they serve in aerodynamics?

Canards, also known as dive planes or dive plates, are usually flat, wedge-shaped, and angled upward toward the back of the car. They serve to direct air upwards, creating a small amount of downforce and helping to fine-tune the balance between downforce on the front and rear tires.

Why is a smooth undertray important for reducing turbulence and drag under a car?

A smooth undertray is important because it covers the nooks and crannies, such as brake lines and exhaust pipes, which can disrupt airflow. This reduces turbulence and drag, allowing air to move more quickly and efficiently under the car, enhancing downforce.

How does a diffuser contribute to the creation of downforce?

A diffuser, typically a rear undertray shaped to gradually increase in size, activates the Venturi effect, causing air to speed up under the car due to the constricted space. According to Bernoulli's principle, this fast-moving air has lower pressure, which results in more downforce as the air rushes to fill the expanding space at the back of the car.

What is the Venturi effect and how is it utilized in car aerodynamics?

The Venturi effect is a phenomenon where a fluid (in this case, air) speeds up as it flows through a more constricted area. In car aerodynamics, it is utilized by diffusers to create faster-moving, low-pressure air under the car, which contributes to increased downforce.

Why are strakes placed in a diffuser?

Strakes are placed in a diffuser to act as vertical dividers that help keep the airflow orderly and reduce turbulence. This ensures that the air flows smoothly and efficiently, enhancing the downforce effect.

What role do side skirts play in maintaining downforce?

Side skirts play a crucial role in blocking high-pressure air from sneaking back under the car and around the sides, which would otherwise increase lift and ruin the downforce that has been created.

Can you explain the Chaparral 2J race car's innovative use of underbody aerodynamics?

The Chaparral 2J race car, developed by Jim Hall, used Lexan side skirts integrated with the suspension to maintain a constant one-inch clearance with the ground, even around turns or over bumps. The car's fans constantly pulled air through the underbody, creating a vacuum that produced up to one and a half G's of downforce.

What is the purpose of vortex generators in car aerodynamics?

Vortex generators are placed in the area around the trailing edge of the roof where the air starts to separate. They generate vortices that help draw the fast-moving air down into the boundary layer, keeping the airflow attached for longer and ensuring that air passes over the rear wing to generate downforce.

How do vortex generators help in maintaining attached airflow over a car's rear wing?

Vortex generators create vortices at their tips that help to energize the boundary layer of air, preventing it from separating and ensuring that the airflow remains attached over the rear wing. This results in more efficient downforce generation.

What is the significance of maintaining smooth airflow in car aerodynamics?

Maintaining smooth airflow without turbulence is crucial in car aerodynamics as it reduces drag, enhances downforce, and allows the car to adhere more closely to the road surface, improving handling and performance.