ABSTRACT
Mach angle The angle of a Mach cone, given by
μ = sin−1 1 M
.
As M → 1, μ → 90◦.
Mach cone For a moving supersonic disturbance, the projection of the sound waves forms a conical volume inside of which the presence of the disturbance is felt by the fluid. Outside the Mach cone, the fluid is unaware of the disturbance. The interior of the Mach cone is often called the zone of action, while the exterior is known as the zone of silence. This phenomena is related to the Doppler effect.
