Pressure drop in pipe flow (Darcy-Weisbach)

Reynolds number, Darcy friction factor (laminar f=64/Re or Colebrook for turbulent flow) and Darcy-Weisbach pressure drop for flow of a Newtonian fluid through a circular pipe.

✓ validated against legacyoriginal: /calculators/pipeflow_fluid.htm

Fluid flow rate, QFlow rate unitPipe diameter, d10⁻³ mPipe length, LmWall roughness (RMS)10⁻⁶ mDensity10³ kg/m³Dynamic viscosity10⁻³ Pa·sPressure drop output unit

Pipe cross section0.79 10⁻⁴ m²

Mean velocity0.21 m/s

Reynolds number2122

Relative roughness, e/d0

Friction factor, f0.03015928947446202

Pressure drop expressed as head, z0.006924248909201796 m

Pressure drop67.90610905254202

Method & references

Darcy-Weisbach equation; laminar f=64/Re, turbulent Colebrook interpolation (Moody diagram).

The computation is a literal port of the original client-side JavaScript from /calculators/pipeflow_fluid.htm. Results are verified equal to the original by an automated golden-master test. No formula has been re-derived or “improved”.

Pressure drop in pipe flow (Darcy-Weisbach) — Engineering ABC