Critical Mach number

Transonic flow patterns on an aircraft wing, showing the effects at and above the critical Mach number.

In aerodynamics, the critical Mach number (Mcr or M*) of an aircraft is the lowest Mach number at which the airflow over some point of the aircraft reaches the speed of sound, but does not exceed it.[1] At the lower critical Mach number, airflow around the entire aircraft is subsonic. Supersonic aircraft such as the Concorde and combat aircraft also have an upper critical Mach number at which the airflow around the entire aircraft is supersonic.[2]

  1. ^ Clancy, L.J. Aerodynamics, Section 11.6
  2. ^ E. Rathakrishnan (3 September 2013). Gas Dynamics. PHI Learning Pvt. Ltd. p. 278. ISBN 978-81-203-4839-4.