IEVref: 113-03-36 ID: Language: en Status: Standard Term: Reynolds number Synonym1: Synonym2: Synonym3: Symbol: Re Definition: quantity of dimension 1 characterizing the flow of a fluid in a given configuration characterized by a specified length l, defined by $R\text{​}e\text{\hspace{0.17em}}=\text{\hspace{0.17em}}\frac{\rho vl}{\eta }\text{\hspace{0.17em}}=\text{\hspace{0.17em}}\frac{vl}{\nu }$, where the fluid is described by its mass density ρ, speed v, dynamic viscosity η, and kinematic viscosity νNOTE 1 The Reynolds number characterizes the relative importance of inertia and viscosity in a fluid flow. NOTE 2 When the Reynolds number is less than a critical value Recrit, laminar flow is stable. For higher values of Re, laminar flow becomes unstable. The critical value depends on the configuration. NOTE 3 In case of a fluid flowing through a circular tube with diameter d, the specified length is l = d, and the critical value of the Reynolds number is Recrit ≈ 2 300. Publication date: 2011-04 Source: Replaces: Internal notes: 2017-06-02: Cleanup - Remove Attached Image 113-03-36en.gif CO remarks: TC/SC remarks: VT remarks: Domain1: Domain2: Domain3: Domain4: Domain5: