What is a Sonic Boom?

Question

It can't simply be the sudden noise from a supersonic vehicle.
Is it to do with the doppler effect, sound multiplying where the vehicle overtakes it's own sound?

One of those things skipped over (almost a pun) very often.
Depends on the rate of acceleration surely, also. I was going to do a simulation program on this, probably still will. Also depends on the observer's position, relative velocity.
I think the worst situation is for example - a jet approaching at relatively the speed of sound, all the sound created during that approach meeting the observer at the same time. . . . . !

Answer 1

A sonic boom is what occurs when a vehicle breaks the sound barrier...

It's complicated, but it is caused by the vehicle breaking through the pressure gradient in front of the craft called a bow shock... A bow shock is an imaginary line separating low from high-pressure regions in air... When the aircraft breaks the sound barrier it creates a point directly in front of the craft where all the pressure waves, or bow shocks, converge...When this occurs the low-pressure region in the rear of the plane and the high-pressure region in front of the plane suddenly rush "into" eachother causing a huge "clap" of converging pressure regions...

Essentially, what you are hearing is trillions of air molecules rushing together in a split second and colliding as pressure is normalized...

Just a little sidenote... the speed of sound changes depending on where you are in the atmosphere... Therefore the higher you go the slower you need to go to break the barrier... The equation for the speed of sound in any medium is...

a = sqrt(gamma*R*T)

where,
gamma = specific heat ratio,constant depending on the medium (1.2 - 1.4 for air)
R = universal gas constant
T = temperature of the medium

Not really clear, but I hope it helped...

Answer 2

I think you've correctly identified "doppler effect" "breaking the sound barrier" and "sonic boom" as related phenomena. Doppler effect happens at all object speeds, breaking the sound barrier happens once at whatever the speed of sound is in the medium (Mach 1), sonic booms happen continuously at or above Mach 1, but only once for each observer. The Mach number is a dimensionless quantity, the ratio of the velocity of the object (or flow) to the speed of sound in the medium. Here's are a couple of useful websites, with pictures explaining what's going on (the second one's got beautiful animations):

http://www.sky-flash.com/boom.htm
http://www.kettering.edu/~drussell/Demos/doppler/doppler.html

I think some (or all) of the following is happening:
1) sound waves bunching up in front of the moving source just below Mach 1
2) air displaced by the vehicle (due to its size) has a significant effect (a tiny but noisy moving source doesn't generate a big boom compared with a quiet but huge moving source)
3) all the frequencies get shifted down really low, so you hear everything in a narrow bass band. This increases the apparent amplitude - i.e. all the high-pitch sounds you wouldn't normally hear become audible.

Aside: On a TV documentary they claimed scientists in the 1940s were worried about vehicles breaking the sound barrier too slowly. They were unsure how much energy could be built up near the vehicle before being released.

Answer 3

When an object, a jet plane, for example, travels faster than the speed of sound, the jet plane will actually speed past the sound wave created by the sound of its engines. When this occurs, a "sonic boom" is created. The "doppler effect" is a completely different phenomenom. The doppler effect can be experienced when, for example, you're watching a car race and you can hear the car approaching rapidly from your right and as it approaches you, the sound increases and as the car races past you, you hear that "zooooom" as the car fades into the distance. That's an example of the doppler effect.

Answer 4

sonic boom is the audible component of a shock wave in air. The term is commonly used to refer to the air shocks caused by the supersonic flight of military aircraft or passenger transports such as Concorde (Mach 2.03, no longer flying) and the Space Shuttle (up to Mach 27). Sonic booms generate enormous amounts of sound energy, sounding much like an explosion; typically the shock front may approach 167 megawatts per square meter, and may exceed 200 decibels.

When an aircraft is near the sound barrier, an unusual cloud sometimes forms in its wake. A Prandtl-Glauert Singularity results from a drop in pressure, because of shock wave formation. This pressure change causes a sharp drop in temperature, which in humid conditions leads the water vapor in the air to condense into droplets and form the cloud.

Answer 5

When a plane travels through the air, it creates waves of pressure around it in all directions. When a plane travels near the speed of sound (Mach 1) these pressure waves get compressed upon each other (simply because they are being generated faster than they can dissipate). Upon reaching approximately 760mph, the waves compress into a single audible wave - a "sonic boom" that trails from the aircraft as it travels through the sky.

Answer 6

maximum definately i will undergo in ideas the days have been a sonic improve became criminal. I heard approximately thyis after asking an analogous question at Wright Patterson Airforce Museum you will possibly be able to right here the improve yet by capacity of the time you do and seek for the airplane it's going to be a techniques out of internet site. look on the SR-seventy one it leaks feul everywhere on take off re-fuels interior the air and heads in the direction of area! They have been going to retire it because of the fact of undercover agent Sattlites yet they discovered a sparkling use for it examining the O-zone so a techniques as i understand they nevertheless use it for that purpose and their is back in law to advance the ban on the sonic improve for a number of motives #a million it hasn't had the end result on the enviroment as they thought. perhaps interior the close to destiny we can hear those booms on a commonplace foundation back they are superb. The Blue Angels have been right here for a airshow and the make a desire fondation have been given there own particular coach considering the fact that alot of the toddlers have been deaf the piolot made a sneak bypass inflicting a very low point sonic improve which i became in a farm field taking %. and he scared me and knocked me on my hind end. It became worth it however seeing the flame popping out the hind end those adult men are superb. In my e book any protection stress pilot is superb no be counted what airplane they fly it takes a particular skills. additionally there are movies accessible approximately whilst they tried to be triumphant in mach-a million or the cost of sound which became achieved by capacity of Chuck Yeager with a pair broken ribs and help stepping into the craft. The evening in the previous he had a horse throw him! relatively some adult men lost their lives attempting to be triumphant in the cost of sound and injury that sound barrier. relatively the planes could no longer structally postpone

Answer 7

It's when a vehicle goes faster than the speed of sound. When a vehicle is traveling, there are sound waves in front of and behind it. When it's traveling faster than the speed of sound, the waves pile up in front of the vehicle, and a wake is created, which induces a sonic boom.

Answer 8

It's a shock wave. Anytime you have something moving faster than the speed of sound, you get one. The pressure wave of a few seconds earlier isn't going fast enough to get out of the way of the one being created now, so the pressure waves pile up in a single wave.

Answer 9

A Sonic Boom is when Guile whips his arms forward, causing a bolt of energy to expend from his arms toward the opponent. It can be performed by pressing back, then forward on the D-pad and the C button.

Answer 10

This has nothing to do with the dopplar effect. A sonic boom is basically the sound from a shockwave in the air. For more on it, visit http://en.wikipedia.org/wiki/Sonic_boom