Mach number

E90366

Mach number is a dimensionless quantity in fluid dynamics and aerodynamics that expresses the ratio of an object's speed to the local speed of sound, commonly used to characterize subsonic, transonic, supersonic, and hypersonic flows.


Statements (49)

Predicate Object
instanceOf aerodynamic parameter
dimensionless quantity
fluid dynamics parameter
physical quantity
alsoDenotedAs Ma
definedAs ratio of flow speed to local speed of sound
dependsOn flow velocity
local speed of sound
temperature of the medium
thermodynamic properties of the fluid
dimension dimensionless
equalsOneMeaning sonic condition
field aerodynamics
fluid dynamics
governs compressibility effects
greaterThanOneMeaning supersonic condition
influences aeroacoustic phenomena
drag characteristics
lift characteristics
pressure distribution around bodies
shock formation
lessThanOneMeaning subsonic condition
namedAfter Ernst Mach
relatedConcept Froude number
Knudsen number
Reynolds number
relatedTo speed of sound
symbol M
typicalRangeHypersonic M ≥ 5
typicalRangeSubsonic M < 0.8
typicalRangeSupersonic 1.2 < M < 5
typicalRangeTransonic 0.8 ≤ M ≤ 1.2
usedFor analyzing expansion waves
analyzing shock waves
classifying aircraft speed regimes
classifying missile speed regimes
classifying spacecraft atmospheric flight regimes
nozzle flow characterization
turbomachinery analysis
wind tunnel testing conditions
usedIn aerodynamic design
compressible flow analysis
gas dynamics
high-speed aerodynamics
usedToCharacterize aerodynamic regimes
hypersonic flow
subsonic flow
supersonic flow
transonic flow

Referenced by (2)

Full triples — surface form annotated when it differs from this entity's canonical label.

Ernst Mach hasEponym Mach number
Mach cone isRelatedTo Mach number