NASA photographed images of supersonic waves created by supersonic aircrafts T-38 Talon.
Source: UOL (Translated to English)
The phenomena is known since the decade of 1940, when aircrafts start to fly above sound speed, but until now it was possible to only listen the sonic bang and generate, through computer, a projection of shock wave.
Through a set of separated images, in the research center Ames, from NASA, in California, researchers were able to make a real photography of phenomena hitting two agency’s T-38 Talon aircrafts. The image series in high resolution shows in details the shock waves spreading in many flight phases, showing quick pressure changes in front of airplane during flight.
The sound speed in air with 20°C is 1234.8 km/h or 343 m/s. This speed is called Mach 1. Mach 2 is twice the sound speed. Sound speed is lower in high altitudes due to low temperature, because air molecules are slower.
When an airplane flies below sound speed, about 1100 km/h, shock waves in front of beak spread sideways. When an aircraft breaks sound barrier, shock waves pressed against the beak are surpassed by the plane, representing a violent sound propagation.
The images has been obtained by Schlieren photography, will be subject to another post.
NASA’s objective is use the data, now displayed in clear form, summed with thousand of studies about the phenomena, to advance in X-59 Quiet SuperSonic Technology program. Project has objective to allow develop a supersonic aircraft which can fly above inhabited areas. The challenge will be create an aerodynamic pattern which don`t generate great pressure areas, therefore, prevent or at least lessen sonic crash.
If project X-59 is successful, could appear commercial supersonic flights, which will be faster, or more silent jet fighters.