Aerodynamics
Introduction
Aerodynamics is the study of how gases interact with moving bodies. As the gas that we encounter most is air, aerodynamics is primarily concerned with the forces of drag and lift, which are caused by air passing over and around solid bodies. Aerodynamics is a sub-field of fluid dynamics, which deals with all types of gases and liquids.
History of Aerodynamics
The principles of aerodynamics have been used and studied throughout history. The earliest recorded efforts to understand and apply the principles of aerodynamics were made by ancient Greek philosophers and inventors. For example, Archimedes' principle of buoyancy, which explains why objects float in water, is a fundamental principle of fluid dynamics.
Fundamental Concepts
Fluid Flow
Fluid flow is a critical concept in aerodynamics. It refers to the way air or any other fluid moves around objects. The behavior of fluid flow can be complex and is determined by the properties of the fluid, the shape of the object, and the speed at which the object is moving through the fluid.
Drag
Drag is a force that acts in the opposite direction to the motion of the object. There are two primary types of drag: form drag and skin friction drag. Form drag, also known as pressure drag, is caused by the shape of the object. Skin friction drag is caused by the friction between the fluid and the surface of the object.
Lift
Lift is the force that acts at a right angle to the direction of motion. In the context of an airplane, lift is the force that opposes the weight of the plane and keeps it in the air. The lift force is generated by the flow of air over the wings of the plane.
Boundary Layer
The boundary layer is the layer of fluid in the immediate vicinity of a bounding surface. In the boundary layer, the effects of viscosity are significant. For an aerodynamic body moving through the air, the boundary layer is the part of the flow close to the body, where viscous forces distort the surrounding non-viscous flow.
Aerodynamics in Practice
Aerodynamics is not just about understanding how air interacts with solid bodies; it's also about using that knowledge to design objects that interact with air in specific ways. This is particularly important in the design of vehicles and structures.
Aerodynamics in Aviation
In aviation, aerodynamics is used to design aircraft that can overcome the force of gravity and resist the force of drag. The shape of an aircraft, the size and shape of its wings, the angle at which it is flown, and the power of its engines all affect its aerodynamic efficiency.
Aerodynamics in Automobile Design
In automobile design, aerodynamics is used to reduce drag, increase fuel efficiency, and improve handling. The shape of a car, its frontal area, and the design of its underbody all affect how air flows around it and, consequently, how it performs.
Aerodynamics in Civil Engineering
In civil engineering, aerodynamics is used to design buildings and bridges that can withstand wind forces. The shape of a building, its orientation, and the materials used in its construction can all affect how it interacts with the wind.