Mach number
Let an agent handle Mach numbers by speed, local conditions and flow regime, and convert to speeds correctly.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify
Researched by: Claude
Purpose and description
Let an agent handle Mach numbers by speed, local conditions and flow regime, and convert to speeds correctly.
A dimensionless quantity equal to the ratio of the speed of a flow or object to the local speed of sound; Mach 1 is sonic, above 1 supersonic, above about 5 hypersonic.
What it is for: Characterising compressible flow in aerodynamics.
It can be compute from speed and sound speed; classify flow regime; design for critical Mach number; convert to km/h at given conditions.
Distinguishing features
Dimensionless ratio
Depends on local temperature
Defines compressibility effects
Not a fixed speed
What it looks like
A number, often displayed on aircraft machmeters.
Physical character
speed of sound at sea level (15 C): about 340 m/s - ISA
hypersonic threshold: about 5 Mach - convention
How it is recognised
Notation M or Ma
Flow regimes: subsonic, transonic, supersonic, hypersonic
Critical Mach number is a design limit
Related models
is a kind of - category
uses - reference
is used in - field
relates to - quantity
In practice
Families and kinds
subsonic flow
transonic flow
supersonic flow
hypersonic flow
critical Mach number
Identifiers
symbol M or Ma notation
Standards and regulation
ISO 2533 standard atmosphere
Supersonic flight restrictions over land
Failure modes and hazards
Converting Mach to speed with the wrong sound speed
Sonic boom effects
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.
Value Computing Mach.
Mach depends on conditions.
Compute
Ratio.
Compute
Mach value.
- What is the Mach number for this speed and temperature? measurement
- Which speed of sound was used? provenance
Conversion
To speed.
Conversion
Conversion.
- What speed does this Mach correspond to at this altitude? measurement
- Under which atmosphere model? provenance
Regime Flow type.
Regimes differ physically.
Class
Subsonic to hypersonic.
Class
Flow regime.
- Which flow regime applies? definition
- What effects appear? definition
Shocks
Shock waves.
Shocks
Shock waves.
- Do shock waves form? boundary
- Where? definition
Design Aircraft.
Design limits use Mach.
Critical Mach
Limit.
Critical
Critical Mach number.
- What is the critical Mach number of this wing? measurement
- What happens beyond it? boundary
Limits
Operating limits.
Limits
Operating limits.
- What is the maximum operating Mach number? measurement
- From which flight manual? provenance
Environment Sonic boom.
Supersonic flight has effects.
Sonic boom
Noise.
Boom
Sonic boom.
- Will the flight produce a sonic boom on the ground? boundary
- How loud? measurement
Rules
Restrictions.
Rules
Flight rules.
- Is supersonic flight allowed here? boundary
- Under which regulation? provenance
What the second pass must settle
- Should flow regimes be separate entries?
- How should atmosphere models be linked?
- How should critical Mach be recorded per aircraft?