What is the sound barrier. Overcoming the sound barrier

What do we imagine when we hear the expression "sound barrier"? A certain limit and barrier, the overcoming of which can seriously affect hearing and well-being. Usually the sound barrier is correlated with the conquest of airspace and the profession of a pilot.

Overcoming this obstacle can provoke the development of chronic diseases, pain syndromes and allergic reactions. Are these views correct or are they stereotypes that have become established? Do they have an actual basis? What is a sound barrier? How and why does it arise? All this and some additional nuances, as well as historical facts related to this concept, we will try to find out in this article.

This mysterious science - aerodynamics

In the science of aerodynamics, designed to explain the phenomena accompanying the movement
Aircraft, there is the concept of "sound barrier". This is a series of phenomena that arise when moving supersonic aircraft or missiles that move at speeds close to the speed of sound or large.

What is a shock wave?

In the process of flowing a supersonic flow in a wind tunnel, a shock wave appears. Her footprints can be seen even with the naked eye. On earth, they are expressed in a yellow line. Outside the cone of the shock wave, in front of the yellow line, on the ground the plane is not even audible. At a speed exceeding sound, the bodies are subjected to flow around the sound stream, which entails a shock wave. It may not be one, depending on the shape of the body.

Shock wave transformation

The front of the shock wave, sometimes called the shock wave, has a rather small thickness, which nevertheless allows us to track the sudden changes in the properties of the flow, the decrease in its velocity relative to the body, and the corresponding increase in the pressure and temperature of the gas in the flow. In this case, the kinetic energy is partially transformed into the internal energy of the gas. The number of these changes directly depends on the speed of the supersonic flow. As the shock wave moves away from the apparatus, pressure drops decrease, and the shock wave is converted to sound. It can reach an outside observer who will hear a characteristic sound resembling an explosion. There is an opinion that this indicates that the device reaches the speed of sound, when the sound barrier leaves the plane behind.

What is really happening?

The so-called moment of overcoming of a sound barrier in practice represents passage of a shock wave with a growing hum of engines of the plane. Now the unit is ahead of the accompanying sound, so the buzz of the engine will be heard after it. Approximation of the speed of aircraft to the speed of sound became possible even during the Second World War, but the pilots noted alarming signals in the work of aircraft.

After the war, many aircraft designers and pilots tried to reach the speed of sound and overcome the sound barrier, but many of these attempts ended tragically. Pessimistic scientists argued that this limit can not be surpassed. By no means experimental, but scientifically, it was possible to explain the nature of the concept of "sound barrier" and to find ways to overcome it.

The recommendations for safe flights

Safe flights at near-sound and supersonic speeds are possible when avoiding a wave crisis, the emergence of which depends on the aerodynamic parameters of the aircraft and the height of the flight. Transitions from one speed level to another should be done as quickly as possible with the use of afterburner, which will help to avoid a long flight in the wave crisis zone. Wave crisis as a concept came from water transport. He appeared at the time of the movement of ships at a speed close to the speed of waves on the surface of the water. Falling into a wave crisis entails a difficulty in the growth of speed, and if it is possible to overcome the wave crisis as simply as possible, then it is possible to enter the regime of gliding or sliding on the water surface.

History in aircraft management

The first person who reached supersonic flight speed on an experimental airplane was American pilot Chuck Yeager. His achievement was noted in history on October 14, 1947. On the territory of the USSR, the sound barrier was overcome on December 26, 1948, by Sokolovsky and Fedorov, who controlled an experienced fighter.

Of civilian aircraft, the first to overcome the sound barrier was the passenger liner Douglas DC-8, which reached 1.012 M on August 21, 1961, or 1262 km / h. The mission was to collect data for the design of the wing. Among the aircraft, the world record was set by a hypersonic air-to-surface aeroballistic missile, which is in service with the Russian army. At an altitude of 31.2 kilometers, the rocket developed a speed of 6389 km / h.

After 50 years after overcoming the sound barrier in the air, Englishman Andy Green made a similar achievement on the car. In free fall, tried to break the record American Joe Kittinger, who conquered the height of 31.5 kilometers. Today, October 14, 2012, Felix Baumgartner set the world record, without the help of transport, in free fall from a height of 39 kilometers, breaking the sound barrier. Its speed thus reached 1342.8 kilometers per hour.

The most unusual overcoming of the sound barrier

Strange to think, but the first invention in the world that overcame this limit was the ordinary whip, which the ancient Chinese invented almost 7 thousand years ago. Almost before the invention of instant photography in 1927, no one even suspected that clicking a whip was a miniature sonic blow. A sharp swing forms a loop, and the speed increases sharply, which confirms the click. The sound barrier is overcome at a speed of about 1200 km / h.

The riddle of the noisiest city

No wonder residents of small towns are shocked when they saw the capital for the first time. The abundance of transport, hundreds of restaurants and entertainment centers are confusing and knocking out of the usual rut. The beginning of spring in the capital usually dates from April, and not the rebellious stormy March. In April there is a clear sky, streams run and buds blossom. People, tired of the long winter, open the windows wide toward the sun, and street noise bursts into the houses. On the street, birds are singing deafeningly, artists are singing, cheerful students recite poems, not to mention the noise in traffic jams and metro. Employees of hygiene departments note that it is harmful for a long time to be in a noisy city. The sound background of the capital consists of transport,
Aircraft, industrial and household noise. The most harmful is just the car noise, as the aircraft fly high enough, and the noise from the enterprises dissolves in their buildings. The constant rumble of cars on especially lively highways exceeds all permissible norms twice. How does the sound barrier overcome in the capital? Moscow is dangerous with an abundance of sounds, so the residents of the capital install double-glazed windows to muffle noise.

How is the sound barrier stormed?

Until 1947, there was no actual data on the person's health in the cockpit, which flies faster than sound. As it turned out, overcoming the sound barrier requires certain strength and courage. During the flight it becomes clear that there are no guarantees of survival. Even a professional pilot can not say for sure whether the design of the airplane will withstand the attack of the elements. In a matter of minutes, the airplane can simply fall apart. How is this explained? It should be noted that movement with subsonic speed creates acoustic waves that run like circles from a fallen stone. Supersonic speed excites shock waves, and a person standing on the ground hears a sound that looks like an explosion. Without powerful computers it was difficult to solve complex differential equations, and we had to rely on blowing models in wind tunnels. Sometimes, in case of insufficient acceleration of an airplane, the shock wave reaches such a level that the windows from the houses fly over which the airplane is flying. Overcome the sound barrier can not everyone, because at this moment it shakes the whole structure, considerable damage can get the attachments of the device. Therefore, for the pilots so strong health and emotional stability. If the flight is gentle, and the sound barrier is overcome as quickly as possible, then neither the pilot nor the possible passengers will feel particularly unpleasant sensations. Especially for the conquest of the sound barrier, a research aircraft was built in January 1946. The creation of the machine was initiated by the order of the Ministry of Defense, but instead of weapons it was stuffed with scientific equipment that tracked the mode of operation of mechanisms and devices. This aircraft was like a modern cruise missile with a built-in rocket engine. The airplane overcame the sound barrier at a maximum speed of 2736 km / h.

Verbal and material monuments to the conquest of the speed of sound

Achievements in overcoming the sound barrier are highly valued today. So, the plane, on which Chuck Yeager first overcame it, is now exhibited at the National Museum of Aeronautics and Cosmonautics, which is in Washington. But the technical parameters of this human invention would not be worth much without the merits of the pilot himself. Chuck Yeager passed the flying school and fought in Europe, after which he returned to England. Unfair evasion from the flights did not break Yeger's spirit, and he obtained admission from the commander-in-chief of the troops of Europe. During the years that remained until the end of the war, Yeager participated in 64 combat sorties, during which he shot down 13 aircraft. Back home Chuck Yeager returned with the title of captain. His description shows phenomenal intuition, incredible coolness and endurance in critical situations. More than once Yeager set records on his plane. His further career was in the Air Force, where he provided training for pilots. The last time Chuck Yeager overcame the sound barrier at 74, which was on the fiftieth anniversary of his flight history and for 1997.

Complex tasks of the creators of aircrafts

World-famous MiG-15 aircraft began to be created at a time when the developers realized that it is impossible to base only on overcoming the sound barrier, but complex technical tasks should be solved. As a result, the machine was created so successful that its modifications were used by different countries. Several different design offices were involved in a kind of competitive struggle, the prize in which was a patent for the most successful and functional aircraft. Developed aircraft with swept wings, which was a revolution in their design. The ideal apparatus was to be powerful, fast and incredibly resistant to any damage from the outside. The swept wings of the aircraft became an element that helped them triple the speed of sound. Then the speed of the aircraft continued to increase, which was explained by the increase in engine power, the use of innovative materials and the optimization of aerodynamic parameters. Overcoming of the sound barrier became possible and real even for the layman, but it does not become less dangerous, therefore, any extremist should reasonably assess his forces before deciding on such an experiment.