Mach number

Mach number (Ma) (pronounced as "mack" in International English or "mock" in the American English) is defined as a ratio of speed to the speed of sound in the medium in case. The Mach number is commonly used both with objects travelling at high speed in a fluid, and with high-speed fluid flows inside channels such as nozzles, diffusers or wind tunnels. As it is defined as a ratio of two speeds, it is a dimensionless number. At standard sea level conditions, Mach 1 is 1,225 km/h (765.6 MPH) in the atmosphere.

Related Topics:
Speed - Speed of sound - Nozzle - Diffuser - Wind tunnel - Dimensionless number - Sea level

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Since the speed of sound increases as the temperature increases, the actual speed of an object travelling at Mach 1 will depend on the fluid temperature around it.

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It can be shown that the Mach number is also the ratio of inertial forces (also referred to aerodynamic forces) to elastic forces.

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The Mach number is named after Austrian physicist and philosopher Ernst Mach.

Related Topics:
Austrian - Ernst Mach

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