Supersonic clap why. What is the sound barrier? How to storm the sound barrier

On October 14, 1947, humanity crossed another milestone. The boundary is quite objective, expressed in a specific physical quantity the speed of sound in air, which in the conditions of the earth’s atmosphere is, depending on its temperature and pressure, within the range of 11001200 km/h. Supersonic speed was conquered by the American pilot Chuck Yeager (Charles Elwood "Chuck" Yeager), a young veteran of World War II, who had extraordinary courage and excellent photogenicity, thanks to which he immediately became popular in his homeland, just like 14 years later Yuri Gagarin.

And it really took courage to cross the sound barrier. Soviet pilot Ivan Fedorov, who repeated Yeager’s achievement a year later, in 1948, recalled his feelings at that time: “Before the flight to break the sound barrier, it became obvious that there was no guarantee of surviving after it. No one knew practically what it was and whether the aircraft’s design could withstand the elements. But we tried not to think about it.”

Indeed, there was no complete clarity as to how the car would behave at supersonic speed. The aircraft designers still had fresh memories of the sudden misfortune of the 30s, when, with the increase in aircraft speeds, they had to urgently solve the problem of flutter - self-oscillations that arise both in the rigid structures of the aircraft and in its skin, tearing the aircraft apart in a matter of minutes. The process developed like an avalanche, rapidly, the pilots did not have time to change the flight mode, and the machines fell apart in the air. For quite a long time mathematicians and designers have been in various countries struggled to solve this problem. In the end, the theory of the phenomenon was created by the then young Russian mathematician Mstislav Vsevolodovich Keldysh (1911–1978), later president of the USSR Academy of Sciences. With the help of this theory, it was possible to find a way to get rid of the unpleasant phenomenon forever.

It is quite clear that equally unpleasant surprises were expected from the sound barrier. Numerical solution of complex differential equations of aerodynamics in the absence of powerful computers was impossible, and one had to rely on “blowing” the models in wind tunnels. But from qualitative considerations it was clear that when the speed of sound was reached, a shock wave appeared near the aircraft. The most crucial moment is breaking the sound barrier, when the speed of the aircraft is compared to the speed of sound. At this moment, the pressure difference on different sides of the wave front quickly increases, and if the moment lasts longer than an instant, the plane can fall apart no worse than from flutter. Sometimes, when breaking the sound barrier with insufficient acceleration, the shock wave created by the aircraft even knocks out the glass from the windows of houses on the ground below it.

The ratio of an aircraft's speed to the speed of sound is called the Mach number (named after the famous German mechanic and philosopher Ernst Mach). When passing the sound barrier, it seems to the pilot that the M number jumps over one in leaps and bounds: Chuck Yeager saw how the speedometer needle jumped from 0.98 to 1.02, after which there was “divine” silence in the cockpit in fact, apparent: just a level The sound pressure in the aircraft cabin drops several times. This moment of “purification from sound” is very insidious; it cost the lives of many testers. But there was little danger of his X-1 aircraft falling apart.

The X-1, manufactured by Bell Aircraft in January 1946, was a purely research aircraft designed to break the sound barrier and nothing more. Despite the fact that the vehicle was ordered by the Ministry of Defense, instead of weapons it was stuffed with scientific equipment that monitors the operating modes of components, instruments and mechanisms. X-1 looked like a modern one cruise missile. It had one Reaction Motors rocket engine with a thrust of 2722 kg. Maximum take-off weight 6078 kg. Length 9.45 m, height 3.3 m, wingspan 8.53 m. Maximum speed at an altitude of 18290 m 2736 km/h. The vehicle was launched from a B-29 strategic bomber and landed on steel “skis” on a dry salt lake.

No less impressive are the “tactical technical specifications"her pilot. Chuck Yeager was born on February 13, 1923. After school I went to flight school, and after graduating I went to fight in Europe. Shot down one Messerschmitt-109. He himself was shot down in the skies of France, but was saved by partisans. As if nothing had happened, he returned to his base in England. However, the vigilant counterintelligence service, not believing the miraculous release from captivity, removed the pilot from flying and sent him to the rear. The ambitious Yeager achieved a reception with the commander-in-chief of the Allied forces in Europe, General Eisenhower, who believed Yeager. And he was not mistaken - in the six months remaining before the end of the war, he made 64 combat missions, shot down 13 enemy aircraft, 4 in one battle. And he returned to his homeland with the rank of captain with an excellent dossier, which stated that he had phenomenal flight intuition, incredible composure and amazing endurance in any critical situation. Thanks to this characteristic, he was included in the team of supersonic testers, who were selected and trained as carefully as later astronauts.

Renaming the X-1 “Glamorous Glennis” in honor of his wife, Yeager set records with it more than once. At the end of October 1947, the previous altitude record of 21,372 m fell. In December 1953 new modification machine X-1A developed a speed of 2.35 M almost 2800 km/h, and six months later rose to a height of 27,430 m. And before that there were tests of a number of fighters launched into series and a run-in of our MiG-15, captured and transported to America during Korean War. Yeager subsequently commanded various Air Force test units both in the United States and at American bases in Europe and Asia, took part in combat operations in Vietnam, and trained pilots. He retired in February 1975 with the rank of brigadier general, having flown 10 thousand hours during his valiant service, tested 180 different supersonic models and collected a unique collection of orders and medals. In the mid-80s, a film was made based on the biography of the brave guy who was the first in the world to conquer the sound barrier, and after that Chuck Yeager became not even a hero, but a national relic. IN last time he took the controls of an F-16 on October 14, 1997, breaking the sound barrier on the fiftieth anniversary of his historic flight. Yeager was then 74 years old. In general, as the poet said, these people should be made into nails.

There are many such people on the other side of the ocean Soviet designers began to try to conquer the sound barrier at the same time as American ones. But for them this was not an end in itself, but a completely pragmatic act. If the X-1 was a purely research machine, then in our country the sound barrier was stormed on prototype fighters, which were supposed to be launched into series to equip Air Force units.

Several design bureaus took part in the competition: Lavochkin Design Bureau, Mikoyan Design Bureau and Yakovlev Design Bureau, which simultaneously developed aircraft with swept wings, which was then a revolutionary design solution. They reached the supersonic finish in this order: La-176 (1948), MiG-15 (1949), Yak-50 (1950). However, there the problem was solved in a rather complex context: war machine must have not only high speed, but also many other qualities: maneuverability, survivability, minimal pre-flight preparation time, powerful weapons, impressive ammunition, etc. and so on. It should also be noted that in Soviet times The decisions of state acceptance commissions were often influenced not only by objective factors, but also by subjective issues associated with the political maneuvers of developers. This whole set of circumstances led to the launch of the MiG-15 fighter, which performed well in the local arenas of military operations in the 50s. It was this car, captured in Korea, as mentioned above, that Chuck Yeager “drove around.”

The La-176 used a record sweep of the wing at that time, equal to 45 degrees. The VK-1 turbojet engine provided a thrust of 2700 kg. Length 10.97 m, wingspan 8.59 m, wing area 18.26 sq.m. Take-off weight 4636 kg. Ceiling 15,000 m. Flight range 1000 km. Armament one 37 mm cannon and two 23 mm. The car was ready in the fall of 1948, and in December its flight tests began in Crimea at a military airfield near the city of Saki. Among those who led the tests was the future academician Vladimir Vasilyevich Struminsky (1914–1998); the pilots of the experimental aircraft were captain Oleg Sokolovsky and colonel Ivan Fedorov, who later received the title of Hero Soviet Union. Sokolovsky, by an absurd accident, died during the fourth flight, having forgotten to close the cockpit canopy.

Colonel Ivan Fedorov broke the sound barrier on December 26, 1948. Having risen to a height of 10 thousand meters, he turned the control stick away from himself and began to accelerate in a dive. “I’m accelerating my 176 from a great height,” the pilot recalled. A tedious low whistle is heard. Increasing speed, the plane rushes towards the ground. On the speedometer scale, the needle moves from three-digit numbers to four-digit numbers. The plane is shaking as if in a fever. And suddenly silence! The sound barrier has been taken. Subsequent decoding of the oscillograms showed that the number M had exceeded one.” This happened at an altitude of 7,000 meters, where a speed of 1.02 M was recorded.

Subsequently, the speed of manned aircraft continued to steadily increase due to an increase in engine power, the use of new materials and optimization of aerodynamic parameters. However, this process is not unlimited. On the one hand, it is inhibited by considerations of rationality, when fuel consumption, development costs, flight safety and other not idle considerations are taken into account. And even in military aviation, where money and pilot safety are not so significant, the speeds of the most “fast” cars are in the range from 1.5M to 3M. It seems like no more is required. (The speed record for manned aircraft with jet engines belongs to the American reconnaissance aircraft SR-71 and is 3.2 M.)

On the other hand, there is an insurmountable thermal barrier: at a certain speed, heating of the car body by friction with air occurs so quickly that it is impossible to remove heat from its surface. Calculations show that when normal pressure this should happen at a speed of about 10M.

Nevertheless, the 10M limit was still reached at the same Edwards training ground. This happened in 2005. The record holder was the X-43A unmanned rocket aircraft, manufactured as part of the 7-year ambitious Hiper-X program to develop a new type of technology designed to radically change the face of future rocket and space technology. Its cost is $230 million. The record was set at an altitude of 33 thousand meters. Used in a drone new system acceleration First, a traditional solid-fuel rocket is fired, with the help of which the X-43A reaches a speed of 7 Mach, and then a new type of engine is turned on - a hypersonic ramjet engine (scramjet, or scramjet), in which ordinary atmospheric air is used as an oxidizer, and gaseous fuel is used as an oxidizer. hydrogen (quite a classic scheme of an uncontrolled explosion).

In accordance with the program, three unmanned models were manufactured, which, after completing the task, were drowned in the ocean. The next stage involves the creation of manned vehicles. After testing them, the results obtained will be taken into account when creating a wide variety of “useful” devices. In addition to aircraft, hypersonic military vehicles - bombers, reconnaissance aircraft and transport aircraft - will be created for NASA's needs. Boeing, which is participating in the Hiper-X program, plans to create a hypersonic airliner for 250 passengers by 2030-2040. It is quite clear that there will be no windows, which break aerodynamics at such speeds and cannot withstand thermal heating. Instead of portholes, there are screens with video recordings of passing clouds.

There is no doubt that this type of transport will be in demand, since the further you go, the more expensive time becomes, accommodating more and more emotions, dollars earned and other components into a unit of time. modern life. In this regard, there is no doubt that someday people will turn into one-day butterflies: one day will be as eventful as today’s (or rather, yesterday’s) human life. And it can be assumed that someone or something is implementing the Hiper-X program in relation to humanity.

Have you heard a loud sound like an explosion when a jet plane flies overhead? This sound occurs when an airplane breaks the sound barrier. What is the sound barrier and why does a plane make such a sound?

As you know, sound travels at a certain speed. Speed ​​depends on altitude. At sea level, the speed of sound is approximately 1220 kilometers per hour, and at an altitude of 11,000 meters - 1060 kilometers per hour. When an airplane flies at speeds close to the speed of sound, it is subjected to certain stresses. When it flies at normal (subsonic) speeds, the front of the plane pushes a pressure wave in front of it. This wave travels at the speed of sound.

The pressure wave is caused by the accumulation of air particles as the aircraft moves forward. The wave moves faster than the plane when the plane flies at subsonic speeds. And as a result, it turns out that air passes unhindered over the surfaces of the aircraft’s wings.

Now let's look at an airplane that flies at the speed of sound. There is no pressure wave in front of the plane. What happens instead is that a pressure wave forms in front of the wing (since the aircraft and the pressure wave are moving at the same speed).

Now a shock wave is formed, which causes large loads in the aircraft wing. The expression “sound barrier” dates back to before airplanes could fly at the speed of sound—and was thought to describe the stresses an airplane would experience at those speeds. This was considered a "barrier".

But the speed of sound is not a barrier at all! Engineers and aircraft designers overcame the problem of new loads. And all we have left from the old views is that the impact is caused by a shock wave when the plane flies at supersonic speeds.

The term "sound barrier" misleadingly describes the conditions that occur when an aircraft is traveling at a certain speed. One might think that when the plane reaches the speed of sound, something like a “barrier” appears - but nothing like that happens!

To understand all this, consider an airplane flying at a low, normal speed. As the aircraft moves forward, a compression wave is formed in front of the aircraft. It is formed by an aircraft moving forward, which compresses air particles.

This wave moves ahead of the aircraft at the speed of sound. And its speed is higher than the speed of an airplane, which, as we have already said, flies at low speed. Moving ahead of the plane, this wave forces air currents to flow around the plane of the plane.

Now imagine that the plane is flying at the speed of sound. No compression waves are formed ahead of the plane, since both the plane and the waves have the same speed. Therefore, the wave forms in front of the wings.

As a result, a shock wave appears, which creates large loads on the aircraft's wings. Before airplanes reached and exceeded the sound barrier, it was believed that such shock waves and g-forces would create something like a barrier for the airplane—the “sound barrier.” However, there was no sound barrier, as aeronautical engineers developed a special aircraft design for this.

By the way, the strong “blow” that we hear when an airplane passes the “sound barrier” is the shock wave that we have already talked about - when the speed of the airplane and the compression wave are equal.

(sometimes more than one, depending on body shape). The photo shows shock waves formed at the tip of the model's fuselage, at the leading and trailing edges of the wing and at the rear end of the model.

At the shock wave front (sometimes also called a shock wave), which has a very small thickness (fractions of mm), almost abruptly dramatic changes properties of the flow - its speed relative to the body decreases and becomes subsonic, the pressure in the flow and the temperature of the gas increase abruptly. Part of the kinetic energy of the flow is converted into internal energy of the gas. All these changes are greater the higher the speed of the supersonic flow. At hypersonic speeds (Mach 5 and above), the gas temperature reaches several thousand degrees, which creates serious problems for vehicles moving at such speeds (for example, the Columbia shuttle collapsed on February 1, 2003 due to damage to the thermal protective shell that occurred during the flight ).

The front of the shock wave, as it moves away from the apparatus, gradually takes on an almost regular conical shape, the pressure drop across it decreases with increasing distance from the top of the cone, and the shock wave turns into a sound wave. The angle between the axis and the generatrix of the cone is related to the Mach number by the relation:

When this wave reaches an observer located, for example, on Earth, he hears a loud sound, similar to an explosion. A common misconception is that this is a consequence of the aircraft reaching the speed of sound, or “breaking the sound barrier.” In fact, at this moment a shock wave passes by the observer, which constantly accompanies the aircraft moving at supersonic speed. Typically, immediately after the “pop”, the observer can hear the hum of the aircraft's engines, which is not heard until the shock wave passes, since the aircraft is moving faster than the sounds it makes. A very similar observation occurs during subsonic flight - an aircraft flying above the observer at high altitude(more than 1 km) is not audible, or rather we hear it with a delay: the direction to the sound source does not coincide with the direction to the visible aircraft for an observer from the ground.

Wave crisis

Wave crisis is a change in the nature of the air flow around an aircraft as the flight speed approaches the speed of sound, accompanied, as a rule, by a deterioration in the aerodynamic characteristics of the aircraft - an increase in drag, a decrease in lift, the appearance of vibrations, etc.

Already during the Second World War, the speed of fighters began to approach the speed of sound. At the same time, pilots sometimes began to observe, incomprehensible at that time, and threatening phenomena occurring with their machines when flying at maximum speeds. An emotional report from a US Air Force pilot to his commander, General Arnold, has been preserved:

“Sir, our planes are already very strict. If cars with even higher speeds appear, we will not be able to fly them. Last week I took down an Me-109 in my Mustang. My plane shook like a pneumatic hammer and stopped obeying the rudders. I couldn't get him out of his dive. Just three hundred meters from the ground, I had difficulty leveling the car...”

After the war, when many aircraft designers and test pilots made persistent attempts to reach the psychologically significant mark - the speed of sound, these strange phenomena became the norm, and many of these attempts ended tragically. This gave rise to the somewhat mystical expression “sound barrier” (fr. mur du son, German Schallmauer- sound wall). Pessimists argued that this limit could not be exceeded, although enthusiasts, risking their lives, repeatedly tried to do this. The development of scientific ideas about supersonic gas movement has made it possible not only to explain the nature of the “sound barrier”, but also to find means of overcoming it.

During subsonic flow around the fuselage, wing and tail of an aircraft, zones of local flow acceleration appear on the convex sections of their contours. When the flight speed of an aircraft approaches sound speed, the local speed of air movement in the zones of flow acceleration may slightly exceed the speed of sound (Fig. 1a). Having passed the acceleration zone, the flow slows down, with the inevitable formation of a shock wave (this is a property of supersonic flows: the transition from supersonic to subsonic speed always occurs discontinuously - with the formation of a shock wave). The intensity of these shock waves is small - the pressure drop at their fronts is small, but they appear in large numbers at once, at different points on the surface of the vehicle, and together they sharply change the nature of the flow around it, with a deterioration in its flight characteristics: the lift of the wing decreases, the air rudders and the ailerons lose their effectiveness, the vehicle becomes uncontrollable, and all this is extremely unstable, and strong vibration occurs. This phenomenon is called wave crisis. When the speed of the vehicle becomes supersonic ( > 1), the flow again becomes stable, although its character changes fundamentally (Fig. 1b).

Rice. 1a. Aerowing in close to sound flow.	Rice. 1b. Aerowing in supersonic flow.

For wings with a relatively thick profile, in conditions of a wave crisis, the center of pressure sharply shifts back and the nose of the aircraft becomes “heavier.” Pilots of piston fighters with such a wing, trying to reach maximum speed in a dive from a high altitude at maximum power, when approaching the “sound barrier”, became victims of a wave crisis - once in it, it was impossible to get out of the dive without reducing the speed, which in turn is very difficult to do in a dive. Most famous case of being pulled into a dive from horizontal flight in the history of domestic aviation is the Bakhchivandzhi disaster when testing the BI-1 rocket at maximum speed. U the best fighters World War II with straight wings, such as the P-51 Mustang or Me-109, the wave crisis at high altitude began at speeds of 700-750 km/h. At the same time, the Messerschmitt Me.262 and Me.163 jets of the same period had swept wings, thanks to which they could reach speeds of over 800 km/h without any problems. It should also be noted that an aircraft with a traditional propeller in horizontal flight cannot reach a speed close to the speed of sound, since the propeller blades enter the wave crisis zone and lose efficiency much earlier than the aircraft. Supersonic propellers with saber blades can solve this problem, but this moment Such screws turn out to be too technically complex and very noisy, which is why they are not used in practice.

Modern subsonic aircraft with cruising flight speeds quite close to sound speed (over 800 km/h) are usually designed with swept wings and thin profile tail surfaces, which allows the speed at which the wave crisis begins to be shifted towards higher values. Supersonic aircraft, which have to pass through a section of wave crisis when gaining supersonic speed, have design differences from subsonic ones, associated both with the characteristics of supersonic air flow and with the need to withstand the loads that arise in conditions of supersonic flight and wave crisis, in particular - triangular in plan, a wing with a diamond-shaped or triangular profile.

• at subsonic flight speeds, speeds at which the wave crisis begins should be avoided (these speeds depend on the aerodynamic characteristics of the aircraft and the flight altitude);
• The transition from subsonic to supersonic speed in jet aircraft should be carried out as quickly as possible, using engine afterburner, in order to avoid a long flight in the wave crisis zone.

Term wave crisis also applies to watercraft moving at speeds close to the speed of waves on the surface of the water. The development of a wave crisis makes it difficult to increase speed. Overcoming a wave crisis by a ship means entering planing mode (sliding of the hull along the surface of the water).

Historical facts

• The first pilot to reach supersonic speed in controlled flight was American test pilot Chuck Yeager in an experimental Bell X-1 aircraft (with a straight wing and rocket engine XLR-11) reached a speed of M=1.06 in a shallow dive. This happened on October 14, 1947.
• In the USSR, the sound barrier was first broken on December 26, 1948 by Sokolovsky, and then by Fedorov, in descending flights on the experimental La-176 fighter.
• The first civilian aircraft to break the sound barrier was the Douglas DC-8 passenger airliner. On August 21, 1961, it reached a speed of 1.012 M or 1262 km/h during a controlled dive from an altitude of 12,496 m. The flight was undertaken to collect data for the design of new leading edges of the wing.
• On October 15, 1997, 50 years after breaking the sound barrier on an airplane, Englishman Andy Green broke the sound barrier in a Thrust SSC car.
• On October 14, 2012, Felix Baumgartner became the first person to break the sound barrier without the aid of any motorized device. vehicle, in free fall during a jump from a height of 39 kilometers. In free fall, he reached a speed of 1342.8 kilometers per hour.

see also

• Thermal barrier (problems in the development of hypersonic aircraft)

Notes

Links

• Theoretical and Engineering Foundations of Aerospace Engineering.

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See what a “sound barrier” is in other dictionaries:

Barrier - all working Barrier discounts in the Home and Cottage category

SOUND BARRIER, the cause of difficulties in aviation when increasing flight speed above the speed of sound (SUPERSONIC SPEED). Approaching the speed of sound, the aircraft experiences an unexpected increase in drag and loss of aerodynamic lift... ... Scientific and technical encyclopedic dictionary

A phenomenon that occurs during the flight of an airplane or rocket at the moment of transition from subsonic to supersonic flight speed in the atmosphere. As the speed of the aircraft approaches the speed of sound (1200 km/h), a thin region appears in the air in front of it, in which... ... Encyclopedia of technology

sound barrier- garso barjeras statusas T sritis fizika atitikmenys: engl. sonic barrier sound barrier vok. Schallbarriere, f; Schallmauer, f rus. sound barrier, m pranc. barriere sonique, f; frontière sonique, f; mur de son, m … Fizikos terminų žodynas

sound barrier- garso barjeras statusas T sritis Energetika apibrėžtis Staigus aerodinaminio pasipriešinimo padidėjimas, kai orlaivio greitis tampa garso greičiu (viršijama kritinė Macho skaičiaus vertė). Aiškinamas bangų krize dėl staiga padidėjusio… … Aiškinamasis šiluminės ir branduolinės technikos terminų žodynas

The sound barrier is a phenomenon that occurs during the flight of an aircraft or rocket at the moment of transition from subsonic to supersonic flight speed in the atmosphere. As the aircraft's speed approaches the speed of sound (1200 km/h), a thin region appears in the air in front of it, in which a sharp increase in pressure and density of the air occurs. This compaction of air in front of a flying aircraft is called a shock wave. On the ground, the passage of the shock wave is perceived as a bang, similar to the sound of a gunshot. Having exceeded the speed of sound, the plane passes through this area of ​​​​increased air density, as if piercing it - breaking the sound barrier. For a long time breaking the sound barrier seemed to be a serious problem in the development of aviation. To solve it, it was necessary to change the profile and shape of the aircraft’s wing (it became thinner and swept-back), make the front part of the fuselage more pointed and equip the aircraft with jet engines. The speed of sound was first exceeded in 1947 by Charles Yeager on a Bell X-1 aircraft (USA) with a liquid rocket engine launched from a Boeing B-29 aircraft. In Russia, the first to break the sound barrier in 1948 was pilot O.V. Sokolovsky on an experimental La-176 aircraft with a turbojet engine.

Video.

Sound speed.

The speed of propagation (relative to the medium) of small pressure disturbances. In a perfect gas (for example, in air at moderate temperatures and pressure) S. z. does not depend on the nature of the propagating small disturbance and is the same both for monochromatic oscillations of different frequencies () and for weak shock waves. In a perfect gas at the considered point in space, the S. z. a depends only on the composition of the gas and its absolute temperature T:
a = (dp/d(())1/2 = ((()p/(())1/2 = ((()RT/(())1/2,
where dp/d(() - derivative of pressure with respect to density for an isentropic process, (-) - adiabatic exponent, R - universal gas constant, (-) - molecular weight (in air a 20.1T1/2 m/s at 0 (°)C a = 332 m/s).
In a gas with physicochemical transformations, for example, in a dissociating gas, S. z. will depend on how - equilibrium or nonequilibrium - these processes occur in the disturbance wave. At thermodynamic equilibrium S. z. depends only on the composition of the gas, its temperature and pressure. When physicochemical processes occur in a nonequilibrium manner, sound dispersion occurs, that is, sound dispersion. depends not only on the state of the medium, but also on the frequency of oscillations (). High-frequency oscillations ((tm), ()) - relaxation time) propagate from the frozen solar system. aj, low-frequency ((,) 0) - with equilibrium S. z. ae, and aj > ae. The difference between aj and ai is, as a rule, small (in air at T = 6000(°)C and p = 105 Pa it is about 15%). In liquids S. z. significantly higher than in gas (in water a 1500 m/s)

What do we imagine when we hear the expression “sound barrier”? A certain limit can seriously affect hearing and well-being. Usually the sound barrier is correlated with the conquest of airspace and

Overcoming this obstacle can provoke the development of chronic diseases, pain syndromes and allergic reactions. Are these ideas correct or do they represent established stereotypes? Do they have a factual basis? What is the sound barrier? How and why does it arise? All this and some additional nuances, as well as historical facts We will try to find out what is associated with this concept in this article.

This mysterious science is aerodynamics

In the science of aerodynamics, designed to explain the phenomena accompanying movement
aircraft, there is the concept of “sound barrier”. This is a series of phenomena that occur during the movement of supersonic aircraft or rockets that move at speeds close to the speed of sound or greater.

What is a shock wave?

As a supersonic flow flows around a vehicle, a shock wave appears in a wind tunnel. Its traces can be visible even to the naked eye. On the ground they are expressed by a yellow line. Outside the shock wave cone, in front of the yellow line, you can’t even hear the plane on the ground. At speeds exceeding sound, bodies are subjected to a flow of sound flow, which entails a shock wave. There may be more than one, depending on the shape of the body.

Shock wave transformation

The shock wave front, which is sometimes called a shock wave, has a fairly small thickness, which nevertheless makes it possible to track abrupt changes in the properties of the flow, a decrease in its speed relative to the body and a corresponding increase in the pressure and temperature of the gas in the flow. In this case, the kinetic energy is partially converted into 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, the pressure drops decrease and the shock wave is converted into a sound wave. 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 has reached the speed of sound, when the plane leaves the sound barrier behind.

What's really going on?

The so-called moment of breaking the sound barrier in practice represents the passage of a shock wave with the increasing roar of the aircraft engines. Now the device is ahead of the accompanying sound, so the hum of the engine will be heard after it. Approaching the speed of sound became possible during the Second World War, but at the same time pilots noted alarming signals in the operation of aircraft.

After the end of the war, many aircraft designers and pilots sought to reach the speed of sound and break the sound barrier, but many of these attempts ended tragically. Pessimistic scientists argued that this limit could not be exceeded. By no means experimental, but scientific, it was possible to explain the nature of the concept of “sound barrier” and find ways to overcome it.

Safe flights at transonic and supersonic speeds are possible by avoiding a wave crisis, the occurrence of which depends on the aerodynamic parameters of the aircraft and the altitude of the flight. Transitions from one speed level to another should be carried out as quickly as possible using afterburner, which will help to avoid a long flight in the wave crisis zone. The wave crisis as a concept came from water transport. It arose when ships moved at a speed close to the speed of waves on the surface of the water. Getting into a wave crisis entails difficulty in increasing speed, and if you overcome the wave crisis as simply as possible, then you can enter the mode of planing or sliding along the water surface.

History in aircraft control

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

Among civilians, the passenger airliner Douglas DC-8 broke the sound barrier, which on August 21, 1961 reached a speed of 1.012 Mach, or 1262 km/h. The purpose of the flight was to collect data for wing design. Among aircraft, the world record was set by a hypersonic air-to-ground aeroballistic missile, which is in service Russian army. At an altitude of 31.2 kilometers, the rocket reached a speed of 6389 km/h.

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

The most unusual breaking of the sound barrier

It’s strange to think, but the first invention in the world to overcome this limit was the ordinary whip, which was invented by the ancient Chinese almost 7 thousand years ago. Almost until the invention of instant photography in 1927, no one suspected that the crack of a whip was a miniature sonic boom. A sharp swing forms a loop, and the speed increases sharply, which is confirmed by the click. The sound barrier is broken at a speed of about 1200 km/h.

The mystery of the noisiest city

It’s no wonder that residents of small towns are shocked when they see the capital for the first time. The abundance of transport, hundreds of restaurants and entertainment centers confuse and unsettle you. The beginning of spring in the capital is usually dated to April, rather than the rebellious, blizzardy March. In April there are clear skies, streams are flowing and buds are blooming. People, tired from the long winter, open their windows wide towards the sun, and street noise bursts into their houses. Birds chirp deafeningly on the street, artists sing, cheerful students recite poetry, not to mention the noise in traffic jams and the subway. Hygiene department employees note that staying in a noisy city for a long time is harmful to health. The sound background of the capital consists of transport,
aviation, industrial and household noise. The most harmful is car noise, since planes fly quite high, and the noise from enterprises dissolves in their buildings. The constant roar of cars on particularly busy highways exceeds all permissible standards twice as much. How does the capital overcome the sound barrier? Moscow is dangerous with an abundance of sounds, so residents of the capital install double-glazed windows to muffle the noise.

How is the sound barrier stormed?

Until 1947, there was no actual data on the well-being of a person in the cockpit of an airplane that flies faster than sound. As it turns out, breaking the sound barrier requires certain strength and courage. During the flight, it becomes clear that there is no guarantee of survival. Even a professional pilot cannot say for sure whether the aircraft’s design will withstand an attack from the elements. In a matter of minutes, the plane can simply fall apart. What explains this? It should be noted that movement at subsonic speed creates acoustic waves that spread out like circles from a fallen stone. Supersonic speed excites shock waves, and a person standing on the ground hears a sound similar to an explosion. Without powerful computers it was difficult to solve complex ones and had to rely on blowing models in wind tunnels. Sometimes, when the plane's acceleration is insufficient, the shock wave reaches such a force that windows fly out of the houses over which the plane flies. Not everyone will be able to overcome the sound barrier, because at this moment the entire structure shakes, and the mountings of the device can receive significant damage. This is why good health and emotional stability are so important for pilots. If the flight is smooth and the sound barrier is overcome as quickly as possible, then neither the pilot nor any possible passengers will feel any particularly unpleasant sensations. A research facility was built specifically to break the sound barrier. aircraft in January 1946. The creation of the machine was initiated by an order from the Ministry of Defense, but instead of weapons it was stuffed with scientific equipment that monitored the operating mode of mechanisms and instruments. This plane was like a modern cruise missile with a built-in rocket engine. The plane broke the sound barrier when maximum speed 2736 km/h.

Verbal and material monuments to conquering the speed of sound

Achievements in breaking the sound barrier are still highly valued today. Thus, the plane in which Chuck Yeager first overcame it is now on display in National Museum Aeronautics and Astronautics, which is located in Washington. But the technical parameters of this human invention would be worth little without the merits of the pilot himself. Chuck Yeager went through flight school and fought in Europe, after which he returned to England. The unfair exclusion from flying did not break Yeager’s spirit, and he achieved a reception with the commander-in-chief of the European troops. In the years remaining until the end of the war, Yeager took part in 64 combat missions, during which he shot down 13 aircraft. Chuck Yeager returned to his homeland with the rank of captain. His characteristics indicate phenomenal intuition, incredible composure and endurance in critical situations. More than once Yeager set records on his plane. His further career was in the Air Force units, where he trained pilots. The last time Chuck Yeager broke the sound barrier was 74 years old, which was on the fiftieth anniversary of his flight history and in 1997.

Complex tasks of aircraft creators

The world-famous MiG-15 aircraft began to be created at the moment when the developers realized that it was impossible to rely only on breaking the sound barrier, but that complex technical problems had to be solved. As a result, a machine was created so successful that its modifications entered service different countries. Several different design bureaus entered into a kind of competitive struggle, the prize in which was a patent for the most successful and functional aircraft. Aircraft with swept wings were developed, which was a revolution in their design. The ideal device had to be powerful, fast and incredibly resistant to any external damage. The swept wings of airplanes became an element that helped them triple the speed of sound. Then it continued to increase, which was explained by an increase in engine power, the use of innovative materials and optimization of aerodynamic parameters. Overcoming the sound barrier has become possible and real even for a non-professional, but this does not make it any less dangerous, so any extreme sports enthusiast should sensibly assess their strengths before deciding to undertake such an experiment.