Talk:Shock wave

"A shock wave travels through most media at a higher speed than an ordinary wave."
can this be cited or clarified? it suggests to me [FTL] — Preceding unsigned comment added by 174.115.5.192 (talk) 01:32, 16 September 2013 (UTC)


 * I am amazed that this blunder has survived so long. A shock wave always travels at the speed of sound in the medium through which it propagates. That is the definition of the speed of sound: it is the speed that a disturbance of pressure or density propagates through a meduim [1].
 * Shock waves may be generated at a greater speed - e.g. the one at the front of a supersonic jet (which propagates from the jet to the observer at Mach 1.0), or the one at the blast front of an explosion, which may be generated at hypersonic speeds whilst the detonation is in progress, but, on completion of the detonation (after milliseconds) detach from the decaying detonation and propagates at Mach 1.0
 * Starling S. G & Woodall A. J. (1961) Physics, Longmans London p. 805  Gpsanimator (talk) 06:52, 13 November 2023 (UTC)

In supersonic flows ...
The section on supersonic flows contains the sentence "Shock waves form when the speed of a fluid changes by more than the speed of sound" which can't be right because it compares a change in speed with a speed. I assume what is meant is "speed of a fluid IS more than the speed of sound" but I don't want to edit an article on a subject I don't understand. oldrider (talk) 23:14, 12 January 2017 (UTC)

The phrase "shock of type 1"
is used but not defined. oldrider (talk) 23:17, 12 January 2017 (UTC)

Photo 2
I don't believe these patterns to be caused by the intersection of shock waves w/ the surface of the water as that would be a conic section basically in reverse of what is shown here. This appears to be a subsonic propagation or pressure wave moving at below Mach 1. Longinus876 (talk) 13:42, 11 December 2019 (UTC)
 * The projectiles would trail a conical shock wave which would intersect the water surface (roughly) as a moving parabola. The expansion of the air inside the cannon creates an expanding spherical wave originating at the cannon tip, which intersects the water surface (roughly) as a circle. This wave is definitely supersonic here. A sonic (Mach 1) wave is basically a shock wave in the limit where it is reversible and there is no energy dissipation involved. Such a wave would be unable to disturb the water surface, by definition. As the supersonic spherical wave expands, it becomes weaker and slower and ultimately becomes a sound wave travelling at the speed of sound. Pressure cannot propagate slower than the speed of sound, and so Mach 1 is the hard lower limit on the speed at which that wave will propagate. Ariadacapo (talk) 14:44, 11 December 2019 (UTC)
 * Ah, correct. I was thinking, wrongly, of a supersonic projectile which this was not.  The hard edge on the pattern tells a story in itself.  Very interesting to me.  Thank you for your correction.  Where would we all be without a little help from our friends,,, or a shove?  Thanks also for the instant response.Longinus876 (talk) 22:07, 11 December 2019 (UTC)

What is the temperature in the 200 nm thick film of the shockwave?
Mentioned are that in the shockwave, the pressure is x25 atmospheric pressure, the thickness of the shockwave film is 200 nm and it is mentioned the temperature increase are what makes shockwaves characteristics and to understand how the ram jet engine works, but I can't find what is the temperature in that film. Thy, SvenAERTS (talk) 13:13, 24 June 2022 (UTC)