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Reynolds Number - Pipe Flow

Reynolds number for pipe flow - the dimensionless parameter separating laminar (Re < 2300), transitional (2300–4000), turbulent (> 4000).

ReynoldsLaminarTurbulent
Re
375,000 -
Regime
Turbulent
Formula, assumptions, and limits

Ship systems mostly turbulent (Re ≥ 10⁴). Laminar flow only in fuel-line slow flow of cold HFO (high ν). Moody chart sections differ between regimes.

Symbol legend

SymbolMeaningUnitSource
Flow velocitym/sQ/A
Pipe inside diametermpipe schedule
Kinematic viscositym²/sfluid temperature