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. Archived 2005-05-10 at the Wayback Machine |
Biot number | surface vs. volume conductivity of solids |
Bodenstein number | residence-time distribution |
Bond number | capillary action driven by buoyancy Archived 2012-03-05 at the Wayback Machine |
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 Archived 2008-06-05 at the Wayback Machine |
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 Archived 2013-12-20 at the Wayback Machine |
Feigenbaum constants | chaos theory (period doubling) |
Fine structure constant | quantum electrodynamics (QED) |
Foppl–von Karman number | thin-shell buckling |
Fourier number | heat transfer |
Fresnel number | slit diffraction |
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 Archived 2009-11-15 at the Wayback Machine |
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) 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 Archived 2005-10-26 at the Wayback Machine |
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 Archived 2015-03-02 at the Wayback Machine |
Rockwell scale | mechanical hardness |
Rossby number | inertial forces in geophysics |
Schmidt number | fluid dynamics (mass transfer and diffusion) Archived 2010-01-24 at the Wayback Machine |
Sherwood number | mass transfer with forced convection |
Sommerfeld number | boundary lubrication Archived 2016-03-16 at the Wayback Machine |
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 Archived 2009-03-25 at the Wayback Machine |
Taylor number | rotating fluid flows |
van 't Hoff factor | quantitative analysis (Kf and Kb) |
Weaver flame speed number | laminar burning velocity relative to hydrogen gas Archived 2017-11-03 at the Wayback Machine |
Weber number | multiphase flow with strongly curved surfaces |
Weissenberg number | viscoelastic flows Archived 2006-11-01 at the Wayback Machine |
Womersley number | continuous and pulsating flows Archived 2009-03-25 at the Wayback Machine |