1. Curvature: An aerofoil has a curved upper surface and a flatter lower surface. This asymmetry in curvature creates a pressure difference between the top and bottom surfaces.
2. Bernoulli's Principle: According to Bernoulli's principle, as the air flows over the aerofoil, the curved upper surface causes the air to travel faster than the air flowing beneath it. This difference in speed results in a pressure difference, with lower pressure above the aerofoil and higher pressure below it.
3. Lift Generation: The pressure difference between the upper and lower surfaces of the aerofoil generates an upward force known as lift. This lift opposes the weight of the aircraft and enables it to fly.
4. Angle of Attack: The angle between the aerofoil's chord line (a reference line drawn from the leading edge to the trailing edge) and the oncoming airflow is known as the angle of attack. The lift generated by the aerofoil increases with increasing angle of attack until a certain critical angle is reached.
5. Flow Separation: At a high angle of attack, the airflow over the upper surface of the aerofoil can separate from the surface. This separation results in a loss of lift and an increase in drag, causing the aircraft to stall.
6. Drag: In addition to lift, an aerofoil also experiences drag, which is the resistance to its movement through the air. Drag is caused by friction between the air and the surface of the aerofoil, as well as by the formation of turbulence and pressure differences.
7. Aerodynamic Efficiency: The shape and design of an aerofoil aim to maximize lift while minimizing drag. This is achieved through careful contouring of the upper and lower surfaces to optimize airflow and reduce pressure drag.
8. Types of Aerofoils: There are various types of aerofoils, each with specific characteristics and applications. Common types include symmetrical aerofoils, cambered aerofoils, supercritical aerofoils, and low-drag aerofoils, among others.
In summary, an aerofoil works by utilizing the principles of aerodynamics, particularly Bernoulli's principle, to generate lift and enable flight. The shape and curvature of the aerofoil, along with its angle of attack, play crucial roles in determining the lift and drag forces acting on the aircraft.