Meaning and Definition of Aerodynamics
What is Aerodynamics? It is the branch of physical science that analyzes the movements of air and other gaseous fluids. Studying the forces established between moving bodies and the air masses that surround them.
Detailed studies on the resistance offered by air and the stability of moving vehicles are essential for the manufacture of modern automobiles, airplanes and all means of transport that move at high speeds.
It is a scientific discipline of enormous practical importance in the military and transportation industries; in fact, its essential objective is to determine the principles that control the movement and stability of airplanes, ships and high-speed trains, as well as those aspects related to the movement of projectiles and missiles.
Furthermore, the laws established through aerodynamic analysis are also applicable in civil engineering. Since they govern the resistance forces presented by bridges and other buildings when they are subjected to the action of high intensity winds.
Theoretical and Experimental Principles
The fundamental objective of aerodynamic studies is to maintain the so-called dynamic equilibrium state . In which the forces developed during its movement must be compensated by those produced by the air masses.
The laws that regulate this discipline use mathematical analysis to describe the ideal conditions for flight or displacement on solid or liquid surfaces.
Although the field of application of the aerodynamic theory covers specialties as diverse as the treatment of air resistance, the ventilation of furnaces or the industrial design of airplanes, trains and automobiles.
His main interest focuses on the description of the forces involved in displacement. of bodies in the air.
This discipline had its origin in the works of Galileu Galilei, Christiaan Huygens and Isaac Newton, who, through different experiences, established the concept of air resistance , also determining its magnitude.
These researchers concluded that the value of this quantity is proportional to the square of the speed of the moving body. The square of the sine of its angle of inclination, the density of the air and the section of the object perpendicular to the direction of the air flow.
On the basis of this relationship, based on mechanical principles , numerous scholars developed the most diverse theories on the effects of viscosity and air lift. A force perpendicular to the direction of the body, which sustains it in motion. Among other concepts that formed the core of aerodynamic principles.
From the basic set of general laws , it is possible to obtain data that, in turn, allow the manufacture of models of airplanes and other vehicles in which the tests that will determine the final design of this equipment are carried out.
Scientists like the Englishman Frederick William Lanchester and Ludwig Prandtl, a German physicist considered the father of modern aerodynamics. They carried out research that revolutionized studies of stability, support and balance of bodies in flight.
His work laid the foundation for solving problems that arose as the speed of vehicles in general, and aircraft in particular, increased.
- Shock waves , formed by the buildup of pressure when the speed of sound is exceeded.
- Boundary layers , in which force displacements caused by viscosity occur.
- Thermal phenomena , characteristic of high speeds.
These are some of the variables that must be considered in the aerodynamic study of devices designed to exceed the speed of sound.
Tests and Means of Observation
To carry out their experiments, most of the laboratories intended to establish the aerodynamic conditioning of means of transport design. They use the so-called wind tunnels, facilities in which a model of the vehicle is submitted to be analyzed to detect forced air currents, speed checked.
There are different types of wind tunnels , classified as open or closed circuit tunnels, and either continuous in operation or with the use of controlled gusts of air.
On the other hand, according to the speed you want to obtain, these facilities can be classified into:
- Subsonic: If the speeds developed in it are lower than the sound
- Supersonic: When they are between five and ten times the value of this speed
- Hypersonic: If the forces developed within it result in speeds greater than ten times the speed of sound.
The tests carried out in these tunnels offer the possibility of calculating the intensity of the forces. Obtaining the result of its three partial components:
- lifting forces
- Vehicle displacement resistance
- Lateral efforts.
In the same way, this analysis allows to optimize the resistance , the design and the position of each element of the structure, by evaluating the forces applied to that component.
In this sense, the interest in visualizing the air outlet currents, during the test of the model in the wind tunnel.
Images can be obtained directly through process photography , under suitable lighting conditions, or through analysis of analytical diagrams.
It is often used to draw curves on a Cartesian axis system. Which represent the main forces that must be analyzed to obtain the desired aerodynamic conditions