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An Air Force T-38C training jet creates shockwaves in the atmosphere as it travels at supersonic speeds in front of the sun
Quote:Using the brilliant light of the overhead sun as a backdrop, NASA researchers have developed a patent-pending method called Background-Oriented Schlieren using Celestial Objects (BOSCO) to make atmospheric distortions from supersonic shockwaves visible.
Invented in 1864 by German physicist August Toepler, who developed the technique by photographing electric sparks in a lab, modern air-to-air schlieren photography uses high-speed, high-definition cameras and advanced imaging software to average out background noise and reveal the shockwaves.
(Schlieren comes from the German word for “streak.”)
Source
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Schlieren photograph of a T-38C traveling faster than sound
Schlieren images can be captured from either the ground or from another aircraft and each method has its own specific advantages—and challenges. The ongoing research is being performed to improve the efficiency and safety of supersonic aircraft for both military and commercial uses.
Quote:“Air-to-air schlieren is an important flight-test technique for locating and characterizing, with high spatial resolution, shock waves emanating from supersonic vehicles,” said Dan Banks, principal investigator on the project at NASA’s Armstrong Flight Research Center at Edwards AFB in California. “It allows us to see the shock wave geometry in the real atmosphere as the target aircraft flies through temperature and humidity gradients that cannot be duplicated in wind tunnels.”
Interesting, that is pretty cool stuff!
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