Reynolds number

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Reynolds number A dimensionless number expressing the balance of viscous and interstitial forces on a small element of moving fluid. The transition from laminar to turbulent flow depends on the Reynolds number (R) which is equal to ρvd/η, where ρ is the fluid density, v the fluid velocity, d the diameter of the pore space through which flow occurs, and η the viscosity. For laminar flow, the Reynolds number is less than 500, while turbulent flow occurs when R is greater than 1000. Darcy's Law for groundwater flow is valid for values of R less than about 1–10.

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Reynolds number

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