Process of Sonic Boom

 Continued from physics lessons Doppler Effect 2

Process of Sonic Boom

F/A-18 Hornet flies at low heightof high  velocity. When is velocity reaches mach 1, a wall vapour around the airplane is formed.

The illustration above represents the sound wave fronts generated by an airplane moving with the same velocity as the sound wave.

The blue points in this illustration are the position of airplane when it emits the sound wave. As the speed of the source is the same as the velocity of the airplane, the sound wave of the point will accumulate and interfere in point. At this point many compressions will be found. As a result the air density at the point is very hight (as well its air pressure).
In order to move faster than the sound wave, the airplane should break throught the barrier of high air pressure.

Sound wave with the veri high amplitude will be heard as an explosion. Although it occurs verry short baut its vibration can break the window’s glass.
This explosion is called sonic boom.
Sometimes people misunderstand about this concept.
They assume that the explosion heard when supersonic airplane flies over them is because it is passing througt a barrier of high air pressure.


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physics education  physics lessons Doppler Effect 2 Process of Sonic Boom for high school