X-Nico

5 unusual facts about Mach number


7.5×55mm Swiss

At 780 m/s (2560 ft/s) muzzle velocity the standard GP 11 ball bullet retained supersonic velocity up to 800 m (875 yards) (V800Mach 1.1) under ICAO Standard Atmosphere conditions at sea level (air density ρ = 1.225 kg/m3).

Doppler radar

Normally it is one or the other; a radar designed for detecting targets from zero to Mach 2 does not have a high resolution in speed, while a radar designed for high resolution velocity measurements does not have a wide range of speeds.

Gain scheduling

For example in an aircraft flight control system, the altitude and Mach number might be the scheduling variables, with different linear controller parameters available (and automatically plugged into the controller) for various combinations of these two variables.

Linear parametric varying control

For example in case of aircraft control, a set of controllers are designed at different gridded locations of corresponding parameters such as AoA, Mach, dynamic pressure, CG etc.

Miller twist rule

For example he states that assuming a mach number of M = 2.5 (or roughly 2800 ft/sec assuming standard conditions at sea level where 1 Mach is roughly 1116 ft/sec) is a safe value to use in regards to velocity.


China Eastern Airlines Flight 583

On April 6, 1993, the McDonnell-Douglas MD-11 was cruising above the Pacific Ocean at Mach 0.84 when a crew member accidentally deployed the slats near the Aleutian Islands.

Lattice Boltzmann methods

It is therefore common to raise the lattice Mach number to something much larger than the real Mach number, and compensating for this by raising the viscosity as well in order to preserve the Reynolds number.

Scramjet

A series of scramjet ground test were completed at NASA Langley Arc-Heated Scramjet Test Facility (AHSTF) at simulated Mach 8 flight conditions.


see also