Full definition
Dimensionless number predicting flow regime in pipes and around bodies: Re = ρVD/μ. Laminar flow: Re < 2300 (orderly layers). Transition zone: 2300 < Re < 4000. Turbulent flow: Re > 4000 (intense mixing, higher heat and mass transfer). Determines the friction factor (f) in the Darcy-Weisbach equation and the convection coefficient.