critical Mach number
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critical Mach number[′krid·ə·kəl ′mäk ‚nəm·bər]
The free-stream Mach number at which a local Mach number of 1.0 is attained at any point on the body under consideration.
critical Mach number (Mcrit)
i. The local Mach number at which airflow at any part of the wing attains a velocity equal to the local speed of sound.
ii. The Mach number at which compressibility effects significantly influence the handling characteristics of an aircraft. This is applicable to subsonic aircraft.