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.
Statements (45)
| Predicate | Object |
|---|---|
| instanceOf |
dimensionless physical constant
ⓘ
empirical constant ⓘ fluid dynamics quantity ⓘ |
| alternativeName | Kármán constant NERFINISHED ⓘ |
| 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 NERFINISHED ⓘ |
| relatedTo |
Prandtl mixing length theory
NERFINISHED
ⓘ
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
NERFINISHED
ⓘ
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 ⓘ |
Referenced by (1)
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