The story
Named after British engineer Osborne Reynolds.
Etymology from Wiktionary, CC BY-SA 4.0.
Reynolds number
Today it means: A dimensionless parameter that determines the behavior of viscous flow patterns. In pipe flow a value less than roughly 2,000 (known as the critical Reynolds number) produces laminar flow, one above about 3,000 produces turbulent flow (intermediate values produce unpredictable behavior). Full definition →