According to "Fact or Fiction", a segment on KGTV in San Diego which aired on Thursday, December 16, 2010, the photos of jets breaking the sound barrier have not been doctored with Photoshop, but display a phenomenon that some scientists describe as the visible manifestation of aircraft "breaking the sound barrier" or creating a "sonic boom".
There is some debate about this issue. Some argue that these vaporous cones only form at "transonic" speeds, just under or over the speed of sound, which may or may not be accompanied by a sonic boom, and strictly speaking have nothing to do with breaking the sound barrier. They're caused by a sudden drop in air pressure around the aircraft from what technically called "Prandtl-Glauert singularity".
In simple terms, it's the point at which a sudden drop in air pressure occurs. Under the right atmospheric conditions, this causes a visible condensation cloud to appear about an aircraft traveling at transonic speeds.
Because these clouds tend to be seen when the aircraft flies at near-sonic speeds, it is frequently said that they "visualize shock waves" or are due to the aircraft "bursting through the sound barrier". Neither statement is true, although the second at least suggests that the phenomena occurs in the near sonic or, in the language of aerodynamics, transonic, regime.
The clouds appear for the same reason that clouds always form, because air has cooled to the point that water vapor in it condenses. Flows around bodies and wings always change the temperature and pressure of the fluid. It is known that lift is caused by pressure differences on top or bottom of a wing or body so that it should follow that the pressure varies from point to point in a flow around an object.
Whatever the reason, the images are striking, and have not been enhanced. They can be enjoyed as technology combining with art to capture a natural phenomenon.
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Comments
Comment originally posed on LinkedIn AviationLink Group on Thursday, December 16, 2010 at 10:57 PM PST:
Thanks for sharing!
My pleasure, Ricardo. Thank you for taking the time to comment.
Cheers,
Joel
Joel Siegfried
National Desk - Airlines/Airport Examiner
Email: ecto@cox.net
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Awesome!
Growing up about half a mile from the old Grumman Aircraft airfield, I can still remember the sound of the sonic boom.
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