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.
References in periodicals archive ?
where [c.sub.0] and M(x) = [v.sub.0](x)/[c.sub.0] represent the adiabatic sound speed and the local Mach number, respectively.
As the local Mach number near the wall is smaller than that near the pipeline center, the contribution of the flow profile on the propagation speed is slight in the downstream propagation.
As a result, in the downstream propagation, the local Mach number near the pipeline wall slightly accelerates the propagation speed compared with that near the pipeline center.