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Engineering Toolbox/Reynolds Number / Flow Regime

Pressure, Level & Process

Reynolds Number / Flow Regime

Screen internal single-phase pipe flow as laminar, transitional or turbulent using average velocity, actual internal diameter and fluid viscosity.

Reynolds calculation

Enter fluid properties at the relevant flowing temperature and pressure.

1 cSt = 1 mm²/s = 1×10⁻⁶ m²/s.

Field use

Flow-regime screening before deeper hydraulic work.

Useful when checking whether internal single-phase pipe flow is clearly laminar or turbulent before applying correlations that depend on flow regime.

Calculation basis

Re = ρvD / μ = vD / ν

For conventional internal-pipe screening: Re < 2300 is shown as laminar, 2300–3999 as transitional, and Re ≥ 4000 as turbulent.

This is a screening tool for single-phase internal flow. It does not calculate friction factor, pressure drop, multiphase regime, erosional velocity, non-Newtonian behavior, fittings loss or final line sizing.

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