# mach number

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mach number
mach.
[1935-40]

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in fluid mechanics, ratio of the velocity of a fluid to the velocity of sound in that fluid, named after Ernst Mach (Mach, Ernst) (1838–1916), an Austrian physicist and philosopher. In the case of an object moving through a fluid, such as an aircraft in flight, the Mach number is equal to the velocity of the object relative to the fluid divided by the velocity of sound in that fluid. Mach numbers less than one indicate subsonic flow; those greater than one, supersonic flow. Fluid flow, in addition, is classified as compressible or incompressible on the basis of the Mach number. For example, gas flowing with a Mach number of less than three-tenths may be considered incompressible, or of constant density, an approximation that greatly simplifies the analysis of its behaviour. For Mach numbers greater than one, shock wave patterns develop on the moving body because of compression of the surrounding fluid. Streamlining alleviates shock wave effects.

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Universalium. 2010.

### Look at other dictionaries:

• Mach number — (mathrm{Ma} or M) (generally pronEng|ˈmɑːk, sometimes IPA|/ˈmɑːx/ or IPA|/ˈmæk/) is the speed of an object moving through air, or any fluid substance, divided by the speed of sound as it is in that substance. It is commonly used to represent an… …   Wikipedia

• Mach number — mäk n a number representing the ratio of the speed of a body to the speed of sound in a surrounding medium (as air) <a Mach number of 2 indicates a speed that is twice that of sound> …   Medical dictionary

• mach number — n. (aeronautics) The ratio of the speed of a moving body to the speed of sound. [WordNet 1.5] …   The Collaborative International Dictionary of English

• Mach number — is the relative velocity of a fluid compared to its sonic velocity. Mach numbers less than 1 correspond to sub sonic velocities, and Mach numbers > 1 correspond to super sonic velocities …   Mechanics glossary

• Mach number — [mäk] n. [after E. Mach (1838 1916), Austrian physicist] [also m n ] a number representing the ratio of the speed of an object to the speed of sound in the surrounding medium, as air, through which the object is moving …   English World dictionary

• Mach number — Macho skaičius statusas T sritis fizika atitikmenys: angl. Mach number vok. Mach Zahl, f rus. число Маха, n pranc. mach, m; nombre de Mach, m; nombre M, m …   Fizikos terminų žodynas

• Mach number — The ratio of the velocity of a body to that of sound in a surrounding medium. A Mach number of 0.8 or 1.2 means that the aircraft is flying at 0.8 or 1.2 times, respectively, the local speed of sound at that ambient temperature. Also known as a… …   Aviation dictionary

• Mach number — Macho skaičius statusas T sritis Energetika apibrėžtis Nedimensinis dydis, lygus dujų greičio ir vietinio (t.y. to paties srauto taško) garso greičio santykiui. Tai vienas iš pagrindinių panašumo kriterijų, apibūdinantis terpės (aplinkos) spūdumo …   Aiškinamasis šiluminės ir branduolinės technikos terminų žodynas

• Mach number — Macho skaičius statusas T sritis Standartizacija ir metrologija apibrėžtis Vidutinio ašinio skysčio arba dujų greičio ir garso skystyje arba dujose greičio dalmuo esant tam tikrai temperatūrai ir slėgiui. Jis skaičiuojamas pagal formulę: M = U/c; …   Penkiakalbis aiškinamasis metrologijos terminų žodynas

• Mach number — Macho skaičius statusas T sritis Gynyba apibrėžtis Vienas iš pagrindinių dujų srauto rodiklių – M=v/a, v – dujų srauto greitis, a – garso greitis tame pačiame dujų srauto taške. Kai M<1, laikoma, kad srauto greitis mažesnis už garso greitį;… …   Artilerijos terminų žodynas

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