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aerodynamics
Значение термина aerodynamics в knolik
aerodynamics - Aerodynamics (Gr. aer; dyn-amis, power)
aerodynamics - Branch of physics devoted to the study of the forces which air can exert on a body; because of either the motion of the body through the air or the motion of the air past the body. Every body moving through air creates a disturbance, and when the air currents resume their former flow behind the moving object, a partial vacuum is created which acts as a drag on the moving object.
Aerodynamically, the perfect shape to induce the minimum of air resistance is that of a drop of water, with the bulbous end in the direction of motion. As it moves forward, an object so shaped evenly parts the air which, flowing smoothly over the surface of the body without inducing any of the eddies that create resistance, slips off the tapered tail without creating a vacuum.
Air resistance is the prime factor in the limitation of the speeds of express railway trains and of racing motor cars. In the case of railway trains, doubling the speed squares the air resistance: when speed is trebled, air resistance multiplies nine times, and so on until the air resistance attains a maximum which the train built on normal lines cannot overcome. This maximum is reached when the train speed is in the region of 100 m.p.h.
Applying the principles of aerodynamics to a railway train means that the front of the engine must be rounded in form, and all projecting parts recessed so that they will not project to create air resistance and thereby reduce speed, while the end of the rear coach must be swept back to a point. A notable example of a train designed on aerodynamic principles is provided by the Silver Jubilee express put into service by the L. and N.E. Ely in 1935.
One of the most important applications of aerodynamics is to the design of aircraft, and has resulted in better shapes for the main components such as wings and fuselage; smoother surfaces with the elimination of discontinuities that can upset airflow; abandoning of all external excrescences; the retraction of undercarriages; the enclosing of cockpits; and better design of engine cowling and cooling systems. A knowledge of aerodynamics is essential to determine such important factors as the strength of the aeroplane structure, the capability of the aircraft to carry its load, and the degree of its controllability and stability.
In its application, particularly to aircraft, aerodynamics is not an exact science, as many of the air forces acting on a body in motion are not directly calculable from first principles, but have to be determined by experiments in wind tunnels (q.v.). Application of aerodynamics to power-driven bodies not only reduces air resistance, but saves fuel consumption in motive power. Experiments have shown that if the modern aircraft could be designed aerodynamically perfect it could fly on one-third of the power now required. See Fairing; Flight; Head Resistance; Streamlining.
Рядом со словом aerodynamics в knolik
| aerodrome | В начало буква "" буквосочетание "" | aero-engines: piston and turbine |
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