Mach number is the ratio of velocity of object and speed of sound.
Mach number is categorized by its value:-
M<0.8 Subsonic
0.8<M<1.2 Transonic
M=1 – Sonic
M>1 Supersonic
M>5 Hypersonic
Tag: Mach Number
M = V/a
M is the local Mach number,
V is the local flow velocity with respect to the boundaries (either internal, such as an object immersed in the flow, or external, like a channel),
a is the speed of sound in the medium, which in air varies with the square root of the thermodynamic temperature.
Mach number (M or Ma) is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound – WIKIPEDIA
