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.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Mach number canonical | 3 |
| Mach 2.5 | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T756181 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Mach number Context triple: [Ernst Mach, hasEponym, Mach number]
-
A.
Mach 1
Mach 1 is a performance-oriented version of the Ford Mustang known for its enhanced power, handling, and distinctive styling cues.
-
B.
SR-71 Blackbird
The SR-71 Blackbird is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed by Lockheed’s Skunk Works and renowned as one of the fastest air-breathing manned aircraft ever built.
-
C.
Swoop
Swoop is the Philadelphia Eagles’ official bald eagle mascot, known for entertaining fans at games and team events.
-
D.
Bell X-1
The Bell X-1 was a pioneering rocket-powered research aircraft that became the first airplane to break the sound barrier in level flight.
-
E.
X-59 QueSST
The X-59 QueSST is a NASA experimental supersonic research aircraft designed to demonstrate quiet sonic boom technology for future low-noise supersonic flight over land.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Mach number Target entity description: 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.
-
A.
Mach 1
Mach 1 is a performance-oriented version of the Ford Mustang known for its enhanced power, handling, and distinctive styling cues.
-
B.
SR-71 Blackbird
The SR-71 Blackbird is a long-range, high-altitude, Mach 3+ strategic reconnaissance aircraft developed by Lockheed’s Skunk Works and renowned as one of the fastest air-breathing manned aircraft ever built.
-
C.
Swoop
Swoop is the Philadelphia Eagles’ official bald eagle mascot, known for entertaining fans at games and team events.
-
D.
Bell X-1
The Bell X-1 was a pioneering rocket-powered research aircraft that became the first airplane to break the sound barrier in level flight.
-
E.
X-59 QueSST
The X-59 QueSST is a NASA experimental supersonic research aircraft designed to demonstrate quiet sonic boom technology for future low-noise supersonic flight over land.
- F. None of above. chosen
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.
this entity surface form:
Mach 2.5