von Kármán constant
E483174
The von Kármán constant is a dimensionless empirical constant that characterizes the logarithmic velocity profile in turbulent boundary layer flows in fluid dynamics.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Kármán constant | 1 |
| von Kármán constant canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4966379 — 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: von Kármán constant Context triple: [Theodore von Kármán, hasEponym, von Kármán constant]
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A.
Knudsen number
The Knudsen number is a dimensionless quantity in fluid dynamics that compares a gas’s molecular mean free path to a characteristic physical length scale, indicating whether continuum or rarefied flow models are appropriate.
-
B.
Knudsen
Knudsen is a Danish-origin surname borne by various notable individuals in fields such as industry, science, and the arts.
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C.
Saffman
Saffman is a surname most notably associated with Philip G. Saffman, a prominent British-American applied mathematician and fluid dynamicist.
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D.
Chandrasekhar number
The Chandrasekhar number is a dimensionless quantity in magnetohydrodynamics that measures the relative importance of magnetic forces compared to viscous forces in a conducting fluid.
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E.
von Klitzing constant
The von Klitzing constant is a fundamental physical constant that characterizes the quantized Hall resistance and provides a precise standard for electrical resistance in quantum metrology.
- 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: von Kármán constant Target entity description: The von Kármán constant is a dimensionless empirical constant that characterizes the logarithmic velocity profile in turbulent boundary layer flows in fluid dynamics.
-
A.
Knudsen number
The Knudsen number is a dimensionless quantity in fluid dynamics that compares a gas’s molecular mean free path to a characteristic physical length scale, indicating whether continuum or rarefied flow models are appropriate.
-
B.
Knudsen
Knudsen is a Danish-origin surname borne by various notable individuals in fields such as industry, science, and the arts.
-
C.
Saffman
Saffman is a surname most notably associated with Philip G. Saffman, a prominent British-American applied mathematician and fluid dynamicist.
-
D.
Chandrasekhar number
The Chandrasekhar number is a dimensionless quantity in magnetohydrodynamics that measures the relative importance of magnetic forces compared to viscous forces in a conducting fluid.
-
E.
von Klitzing constant
The von Klitzing constant is a fundamental physical constant that characterizes the quantized Hall resistance and provides a precise standard for electrical resistance in quantum metrology.
- F. None of above. chosen
Statements (45)
| Predicate | Object |
|---|---|
| instanceOf |
dimensionless physical constant
ⓘ
empirical constant ⓘ fluid dynamics quantity ⓘ |
| alternativeName |
Kármán constant
ⓘ
linked to:
von Kármán constant
|
| appearsInEquation |
U(z) = (u*/κ) ln(z/z0) for neutral atmospheric stratification
ⓘ
u+ = (1/κ) ln y+ + B ⓘ |
| appliesTo |
turbulent flow over rough walls
ⓘ
turbulent flow over smooth walls ⓘ |
| approximateRange | 0.38–0.42 ⓘ |
| assumedConstantFor | high-Reynolds-number wall-bounded turbulence ⓘ |
| category |
boundary layer parameter
ⓘ
turbulence constant ⓘ |
| characterizes | logarithmic velocity profile in turbulent boundary layers ⓘ |
| dependsWeaklyOn |
Reynolds number in some experimental datasets
ⓘ
surface roughness in some formulations ⓘ |
| dimension | dimensionless ⓘ |
| field |
boundary layer theory
ⓘ
fluid dynamics ⓘ turbulence ⓘ |
| historicalOrigin | derived from analysis of turbulent boundary layers by Theodore von Kármán ⓘ |
| namedAfter | Theodore von Kármán ⓘ |
| relatedTo |
Prandtl mixing length theory
ⓘ
Reynolds-averaged Navier–Stokes modeling ⓘ friction velocity ⓘ log-law region of turbulent flow ⓘ logarithmic law of the wall ⓘ roughness length ⓘ wall shear stress ⓘ |
| role | slope parameter of the logarithmic velocity profile ⓘ |
| status | empirically determined constant ⓘ |
| symbol | κ ⓘ |
| typicalValue | 0.41 ⓘ |
| uncertaintySource | experimental scatter in turbulent boundary layer measurements ⓘ |
| usedBy |
atmospheric scientists
ⓘ
engineers ⓘ hydraulic engineers ⓘ oceanographers ⓘ |
| usedIn |
Monin–Obukhov similarity theory
ⓘ
atmospheric surface layer similarity theory ⓘ law of the wall ⓘ surface flux parameterizations ⓘ turbulent boundary layer modeling ⓘ wall functions in computational fluid dynamics ⓘ wall-bounded turbulent flow analysis ⓘ wind profile estimation in the atmospheric boundary layer ⓘ |
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: von Kármán constant Description of subject: The von Kármán constant is a dimensionless empirical constant that characterizes the logarithmic velocity profile in turbulent boundary layer flows in fluid dynamics.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: von Kármán constant