17.4. Applications of Drag and Lift

Good morning, let us have a today class on drag and lift which is the last class of this course okay.

The lecture begins with a greeting and sets the context for discussing drag and lift. These terms are fundamental in fluid mechanics as they describe the forces acting on bodies moving through fluids, such as air or water.

Imagine a cyclist racing against the wind. The forces of drag act against the cyclist’s motion, making it harder to speed up. Understanding drag helps cyclists design their gear and position for better performance.

To really design a fuel efficient car or you talk about design wind turbine all he needs a information knowledge on this drag and the lift...

This section emphasizes the significance of understanding drag and lift in designing various vehicles and structures. Engineers use this knowledge to create efficient designs that minimize drag and enhance lift, such as fuel-efficient cars and effective wind turbines.

Think of how car manufacturers design vehicles to reduce wind resistance. By smoothing out shapes and reducing drag, they can create cars that save fuel and go faster.

When you have a cyclist okay driving a bicycles okay if you can look at recent Olympics and all if you see these persons lean seat okay as to reduce the drag forces...

The example of cyclists in the Olympics showcases how athletes adjust their positions to decrease drag. By leaning forward, cyclists minimize their frontal area, thus reducing the drag acting against them.

Picture a swimmer trying to glide through the water. By streamlining their body, they reduce water resistance, allowing them to swim faster with less effort.

So most often we define the drag force is a functions of half rho v square is a dynamic pressures as we discussed earlier multiplied with a Cd...

Drag force can be calculated using the formula: F_d = (1/2) * ρ * v^2 * C_d * A, where ρ is the fluid density, v is the velocity, C_d is the drag coefficient and A is the frontal area. This formula helps engineers predict how much force a body will face as it moves through a fluid.

Picture a parachute. When the parachute opens, it increases the frontal area (A). This results in a larger drag force that helps slow down the descent, illustrating how changes to the area impact drag.

The coefficients of drag will more details will come which will be the is nothing else force of drag divided by dynamic pressures...

The drag coefficient (C_d) is a dimensionless number that characterizes how aerodynamic or hydrodynamic a shape is. It’s defined as the ratio of the drag force to the dynamic pressure acting on the object. A lower C_d value means that the body has less drag.

Think of an arrow flying through the air. Its sleek shape gives it a low drag coefficient, allowing it to travel further than a flat piece of paper with a high drag coefficient.

If you look at the wind turbines you can talk about the cyclist, we talk about swimmers or you talk about any gymnastics...

Drag and lift are present in numerous everyday activities and technologies. For instance, wind turbines harness lift to generate power, while athletes optimize their movements to reduce drag for better performance, highlighting the importance of these forces in various fields.

Consider how aerodynamics affects a football. The shape of the ball, combined with spinning, influences its flight path. Players learn to throw with a spiral to reduce drag and make the ball travel farther.

As I said it that the drag coefficient FD it has is two component okay. FD will have a two component one will be FD as a frictions and FD for the pressure or the firm drag...

In engineering applications, drag is often broken down into two components: friction drag (due to contact with the fluid) and pressure drag (due to shape). Understanding both helps engineers design more effective structures and vehicles.

Imagine designing a bridge. Engineers must consider wind forces acting on it. By understanding drag forces, they can design to withstand high winds, ensuring safety and stability.

Now let us talk about drag and lift friction and pressure drags okay which is definitions wise how the drag coefficients are common geometry...

The conclusion summarizes the principles of drag and lift, stating that understanding these forces is crucial for designing everything from vehicles to structures, emphasizing the relationship between shape and drag coefficients.

Think of a basketball player’s jump shot. The lift generated by the ball going upward is essential for making the shot; understanding lift here helps improve shooting techniques.

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