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 the pilot.

Overcoming this obstacle can provokedevelopment of chronic diseases, pain syndromes and allergic reactions. Are these views correct or are they stereotypes that have been 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 a concept"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 supersonic flow past the apparatusflow in the wind tunnel there is a shock wave. Her footprints can be seen even with the naked eye. On the ground 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, which is sometimes calledshock wave, has a rather small thickness, which allows one to nevertheless track the discontinuous 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 the sonicThe barrier in practice is the passage of a shock wave with the increasing rumble of the aircraft engines. 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 pilots noted alarm signals in the work of aircraft.

After the war, many aircraft designers andThe 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. Far from 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 to near-sound andSupersonic 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 produced flight. Transitions from one speed level to another should be done as quickly as possible with the application 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 supersonicflight speed on an experimental aircraft, is an 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 ran an experienced fighter.

From civilian aircraft I was the first to overcomesound barrier passenger liner Douglas DC-8, which on August 21, 1961 reached a speed of 1.012 M, 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 barrierin 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 aid 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 world's first invention,overcame this limit, was the usual whip, which was invented by the ancient Chinese 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 rises 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 experience a shock,seeing 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, creeks 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 the noise.

How is the sound barrier stormed?

Until 1947, there was no evidence offeeling the person in the cockpit of the plane, which flies faster than the 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 the movement with subsonic speed creates acoustic waves that scatter 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, with insufficient acceleration of the aircraft, 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 shaking the whole structure, significant damage can get the attachment device. Therefore, strong health and emotional stability are so important for pilots. If the flight goes gently, and the sound barrier is overcome as quickly as possible, neither the pilot nor 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 highare still 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. In his description, phenomenal intuition, incredible coolness and endurance in critical situations are indicated. More than once Yeager set records on his plane. His further career was in the Air Force, where he conducted training for pilots. The last time Chuck Yeager overcame the sound barrier at 74 years, which was on the fiftieth anniversary of his flight history and for 1997.

Complex tasks of the creators of aircraft

Known for the whole world MiG-15 aircraftcreate 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 adopted 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 had 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 aircraft continued to increase, which was explained by the increase in engine power, the use of innovative materials and 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 strength before deciding on such an experiment.