Supersonic aircraft Supersonic aircraft A supersonic aircraft is an aircraft able to fly faster than the speed of sound (Mach number 1). Supersonic aircraft were developed in the second half of the twentieth century and have been used almost entirely for research and military purposes. Only two, Concorde and the Tupolev Tu-144, ever entered service for civil use as airliners. Fighter jets are the most common example of supersonic aircraft. The aerodynamics of supersonic flight is called compressible flow because of the compression (physics) associated with the shock waves or "sonic boom" created by any object travelling faster than sound. Aircraft flying
Piston effect sound. Instead, tunnel boom results from the structure of the tunnel preventing the air around the train from escaping in all directions. As a train passes through a tunnel, it generates compression waves in front of it. These waves coalesce into a shock wave that generates a loud boom when it reaches the tunnel exit. The strength of this wave is proportional to the cube of the train's speed, so the effect is much more pronounced with faster trains. Tunnel boom can disturb residents near the mouth of the tunnel, and it is exacerbated in mountain valleys where the sound