I bet the question didn’t make much sense. What I mean is, when an aircraft passes the speed of sound, it creates a sonic boom. We got that down. But after it does its main flying and slows down to land, does it create another sonic boom when it reaches the speed of sound again while slowing down?
An aircraft creates a sonic boom for as long as it is flying above the speed of sound. The sonic boom stops when it slows below the speed of sound.
The boom is not a one-time phenomenon that occurs when crossing the sound barrier. It is a continuous phenomenon that exists for as long as the aircraft exceeds the speed of sound. On the ground, the boom is heard at a given point once as the aircraft passes, but the boom itself travels with the aircraft and sweeps the ground below.
The boom is just a shock wave that is produced by the aircraft as it moves through the air at supersonic speeds. The shock wave fans outward from the aircraft at greater than the speed of sound, but rapidly slows to the speed of sound and is heard as a bang or boom at long distances. Most aircraft actually produce two shock waves, one at the front and one at the back of the aircraft, and so a double boom may be heard if one is close enough, otherwise the two may blend into a single rumble.
January 14th, 2010 at 10:46 am
The sonic boom travels with the plane. It is not just a single noise when the speed of sound is exceeded. In other words, it is a continuous sound. You hear it when the plane passes over, the guy in the next county hears it when the plane passes over, etc.
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January 14th, 2010 at 11:05 am
Yes – I will give you an example
When the Space Shuttle returns to Earth and slows down for landing you will hear a sonic boom – in fact some times you can hear Mission Control mentioning the sonic boom.
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January 14th, 2010 at 11:40 am
The sonic boom occurs constantly the entire time the plane is going supersonic, not just once when the plane passes the speed of sound.
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January 14th, 2010 at 11:52 am
An aircraft creates a sonic boom for as long as it is flying above the speed of sound. The sonic boom stops when it slows below the speed of sound.
The boom is not a one-time phenomenon that occurs when crossing the sound barrier. It is a continuous phenomenon that exists for as long as the aircraft exceeds the speed of sound. On the ground, the boom is heard at a given point once as the aircraft passes, but the boom itself travels with the aircraft and sweeps the ground below.
The boom is just a shock wave that is produced by the aircraft as it moves through the air at supersonic speeds. The shock wave fans outward from the aircraft at greater than the speed of sound, but rapidly slows to the speed of sound and is heard as a bang or boom at long distances. Most aircraft actually produce two shock waves, one at the front and one at the back of the aircraft, and so a double boom may be heard if one is close enough, otherwise the two may blend into a single rumble.
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January 14th, 2010 at 12:19 pm
It creates a sonic boom from the time it goes supersonic to the time it slows trans-sonic.
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January 14th, 2010 at 1:09 pm
Techwing is correct. You can think of a sonic boom as being like standing on a shore and watching a boat pass by. The boat creates a bow wave that propagates out from the path that the boat is taking. If it is really a big boat or if he is pouring the coals to it, there will be another wave trailing off the stern. Eventually, you will see those waves lap up onto the shore. By the time they reach you, they probably look like one set of waves. This analogy is comparable to standing on the ground and watching an aircraft fly over supersonically. That aircraft creates waves that propagate outward in all directions from the line of flight. When the aircraft pulls the wave across your location, you hear the boom. When the aircraft falls below supersonic speed, the waves are no longer generated at the point of origin – the aircraft. So the waves no longer propagate and no longer reach the ground.
The Shuttle does not create shock waves because it is slowing down. It creates shock waves because it is moving at several times the speed of sound as it passes over the heads of the observers. Once it drops below the speed of sound, it no longer creates the shock.
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January 14th, 2010 at 1:46 pm
To answer your question correctly, the term sound barrier is actually a misnomer that is technically inaccurate. The phrase was originally coined during the 1930s as fluid dynamics research pushed closer and closer to the speed of sound. It was soon discovered that the aerodynamic force of drag grew increasingly large when approaching Mach 1, a phenomenon we now recognize as the transonic drag rise caused by the formation of shock waves.
This behavior led many to believe that there was some sort of physical barrier that would prevent an object from reaching supersonic speeds. However, this belief turned out to be incorrect, and supersonic vehicles are commonplace today. We know today that there is no "sound barrier," and the antiquated term ought to be discontinued. Regardless, the phrase has taken on a life of its own and is still widely used by the general public, though you’ll rarely find any aerospace engineers who do so.
So the answer is NO. You only really hear it once as the aircraft passes through it, not coming back out.
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