Name |
Field of application |
---|

Abbe number |
optics (dispersion in optical materials) |

Albedo |
climatology, astronomy (reflectivity of surfaces or bodies) |

Archimedes number |
motion of fluids due to density differences |

Bagnold number |
flow of grain, sand, etc. [1] |

Biot number |
surface vs. volume conductivity of solids |

Bodenstein number |
residence-time distribution |

Bond number |
capillary action driven by buoyancy [2] |

Brinkman number |
heat transfer by conduction from the wall to a viscous fluid |

Brownell Katz number |
combination of capillary number and Bond number |

Capillary number |
fluid flow influenced by surface tension |

Coefficient of static friction |
friction of solid bodies at rest |

Coefficient of kinetic friction |
friction of solid bodies in translational motion |

Colburn j factor |
dimensionless heat transfer coefficient |

Courant-Friedrich-Levy number |
numerical solutions of hyperbolic PDEs[3] |

Damköhler numbers |
reaction time scales vs. transport phenomena |

Darcy friction factor |
fluid flow |

Dean number |
vortices in curved ducts |

Deborah number |
rheology of viscoelastic fluids |

Decibel |
ratio of two intensities of sound |

Drag coefficient |
flow resistance |

e |
mathematics |

Eckert number |
convective heat transfer |

Ekman number |
geophysics (frictional (viscous) forces) |

Elasticity (economics) |
widely used to measure how demand or supply responds to price changes |

Eötvös number |
determination of bubble/drop shape |

Euler number |
hydrodynamics (pressure forces vs. inertia forces) |

Fanning friction factor |
fluid flow in pipes [4] |

Feigenbaum constants |
chaos theory (period doubling) [5] |

Fine structure constant |
quantum electrodynamics (QED) |

Foppl–von Karman number |
thin-shell buckling |

Fourier number |
heat transfer |

Fresnel number |
slit diffraction [6] |

Froude number |
wave and surface behaviour |

Gain |
electronics (signal output to signal input) |

Galilei number |
gravity-driven viscous flow |

Graetz number |
heat flow |

Grashof number |
free convection |

Hatta number |
adsorption enhancement due to chemical reaction |

Hagen number |
forced convection |

Karlovitz number |
turbulent combustion |

Knudsen number |
continuum approximation in fluids |

Kt/V |
medicine |

Laplace number |
free convection within immiscible fluids |

Lewis number |
ratio of mass diffusivity and thermal diffusivity |

Lockhart-Martinelli parameter |
flow of wet gases [7] |

Lift coefficient |
lift available from an airfoil at a given angle of attack |

Mach number |
gas dynamics |

Magnetic Reynolds number |
magnetohydrodynamics |

Manning roughness coefficient |
open channel flow (flow driven by gravity) [8]PDF (109 KiB) |

Marangoni number |
Marangoni flow due to thermal surface tension deviations |

Morton number |
determination of bubble/drop shape |

Nusselt number |
heat transfer with forced convection |

Ohnesorge number |
atomization of liquids, Marangoni flow |

Péclet number |
advection–diffusion problems |

Peel number |
adhesion of microstructures with substrate [9] |

Pi |
mathematics (ratio of a circle's circumference to its diameter) |

Poisson's ratio |
elasticity (load in transverse and longitudinal direction) |

Power factor |
electronics (real power to apparent power) |

Power number |
power consumption by agitators |

Prandtl number |
forced and free convection |

Pressure coefficient |
pressure experienced at a point on an airfoil |

Radian |
measurement of angles |

Rayleigh number |
buoyancy and viscous forces in free convection |

Refractive index |
electromagnetism, optics |

Reynolds number |
flow behavior (inertia vs. viscosity) |

Richardson number |
effect of buoyancy on flow stability [10] |

Rockwell scale |
mechanical hardness |

Rossby number |
inertial forces in geophysics |

Schmidt number |
fluid dynamics (mass transfer and diffusion) [11] |

Sherwood number |
mass transfer with forced convection |

Sommerfeld number |
boundary lubrication [12] |

Stanton number |
heat transfer in forced convection |

Stefan number |
heat transfer during phase change |

Stokes number |
particle dynamics |

Strain |
materials science, elasticity |

Strouhal number |
continuous and pulsating flow [13] |

Taylor number |
rotating fluid flows |

van 't Hoff factor |
quantitative analysis (K_{f} and K_{b}) |

Weaver flame speed number |
laminar burning velocity relative to hydrogen gas [14] |

Weber number |
multiphase flow with strongly curved surfaces |

Weissenberg number |
viscoelastic flows [15] |

Womersley number |
continuous and pulsating flows [16] |