local Mach number

local Mach number

[′lō·kəl ′mäk ‚nəm·bər] (aerospace engineering) The Mach number of an isolated section of an airplane or its airframe.

local Mach number

The ratio of the free-stream flow to the local speed of sound. The speed of sound varies because of temperature changes around the aircraft, and thus the local Mach number may be more, less, or equal to the free-stream Mach number. See free-stream Mach number.