Re = ρ·V·D/μ for an internal pipe flow. Determines whether the flow is laminar (< 2300), transitional, or turbulent (> 4000).
Formula
$$ \text{Re} = \frac{\rho \cdot V \cdot D}{\mu} $$
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $ρ$ | Fluid density | kg/m³ | ISO 8217 / water table |
| $V$ | Average velocity | m/s | derived |
| $D$ | Pipe internal diameter | m (mm/1000) | pipe spec |
| $μ$ | Dynamic viscosity | Pa·s (cP/1000) | fluid property |
Sources
- White - Fluid Mechanics.