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.

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All labels observed (2)

Label Occurrences
Mach number canonical 3
Mach 2.5 1

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

How these facts were elicited

The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.

Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10.

# Requirements
- If you don't know the subject at all, return an empty list.
- If the subject is not a named entity, return an empty list.
- Include at least one triple where predicate is "instanceOf".
- Do not get too wordy.
- Separate several objects into multiple triples with one object.
Input
Subject: Mach number
Description of subject: 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.

Referenced by (4)

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

Ernst Mach hasEponym Mach number
Mach cone isRelatedTo Mach number
Mach notableVersion Mach number
this entity surface form: Mach 2.5
Froude number relatedTo Mach number