Super Sonic Flight: Frequency Changes in Mach Cone & Shockwave

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Discussion Overview

The discussion revolves around the behavior of sound emitted from a supersonic source, particularly focusing on the implications of continuously changing frequency during flight and its relationship to the Mach cone and shockwave formation. The scope includes theoretical considerations and technical explanations related to supersonic flight and sound propagation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions the implications of changing frequency of sound emitted from a supersonic source during flight.
  • Another participant seeks clarification on what frequency is being referred to in the discussion.
  • A participant mentions that the shock wave is a pressure wave created by the aircraft, suggesting it does not have a defined frequency.
  • Another participant counters that while the shock wave itself may not have a specific frequency, it can have a broad spectrum of frequencies due to its nature as a pressure wave.
  • One participant references Air-Force experiments involving ionization of air to potentially mitigate shock wave effects, although the connection to frequency changes is unclear.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the shock wave and its relationship to frequency, with no consensus reached on the implications of changing frequency during supersonic flight.

Contextual Notes

There are unresolved assumptions regarding the relationship between frequency changes and shock wave characteristics, as well as the specific conditions under which the Air-Force experiments were conducted.

brasilr9
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If a sound source flying at a speed faster than a sound, it will produce a Mach cone and shockwave, like the figure. But what will happen if the frequency changes continuously during the flight?

thanks for help!
 

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What frequency are you talking about?
 
The frequency of the emitted sound from the source.
 
I'm not understanding the question.
But, if you are looking for a way to mitigate the shock wave, I read somewhere about Air-Force experiments that ionized the surrounding air while in-flight and thus affected the formation of the shock wave.
 
A supersonic shock wave is not the sound of the airplane, it's a pressure wave pushed ahead of the plane by the wings, nose, etc. And, afaik, since it's a shock, it doesn't really have any frequency.
 
russ_watters said:
A supersonic shock wave is not the sound of the airplane, it's a pressure wave pushed ahead of the plane by the wings, nose, etc. And, afaik, since it's a shock, it doesn't really have any frequency.

Actually, it has a very broad spectrum of frequencies. (A temporally narrow pulse has a very broad Fourier transform and vice versa.)
 

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