George Gabriel Stokes fluid dynamics |

## Reynolds number

A property of a flowing gas or liquid, the ratio of its inertial and viscous forces and proportional to its speed for a given length, the Reynolds number helps predict the scaling effects and the transition of laminar to turbulent flow of fluids in pipes, of air over airplane wings, and of weather conditions. A high Reynolds number means that inertial forces outweigh viscous forces, and a low Reynolds number means that viscous forces outweigh inertial forces.

## Reynolds things

Stokes introduced the concept in 1851. Osborne Reynolds popularized it in 1883. Arnold Sommerfeld named the number in 1908 to honor Reynold. Can a similar story be told about the Reynolds transport theorem, Reynolds decomposition, Reynolds stress, Reynolds-averaged Navierâ€“Stokes equations, Reynolds dilatancy, and the Reynolds operator?

## Your number

Your number is not dimensionless. Your number is a measure of you. Your number brings joy to some, and irritates others beyond measure. Some think they have your number; others know it as a mystery of mysteries.

Osborne Reynolds publicized the work of George Gabriel Stokes by varying the velocity of water in a glass pipe and introducing into it a narrow stream of dyed water to demonstrate the onset of turbulent flow. Reynolds made many contributions to the fields of fluid mechanics, fluid dynamics, and heat transfer as both a scientist and an engineer.

See also in

The book of science:D’Alembert’s paradox—Jean le Rond d’AlembertThermal transpiration—Osborne Reynolds, Martin KnudsenEkman transport—Vagn Walfrid Ekman, Fridtjof NansenBoundary layer—Ludwig PrandtlReadings on wikipedia:

Other readings: