How do I find the Darcy friction factor?

For laminar flow, f = 64/Re. For turbulent flow, use the Colebrook-White equation or the explicit Swamee-Jain approximation: f = 0.25/[log(ε/3.7D + 5.74/Re⁰·⁹)]².

What is pipe roughness ε?

Pipe roughness ε is the average surface irregularity height. New commercial steel ε ≈ 0.046 mm, cast iron ε ≈ 0.26 mm, concrete ε ≈ 0.3–3 mm, PVC ε ≈ 0.0015 mm.

When should I use Hazen-Williams instead?

Hazen-Williams is simpler but only valid for water at normal temperatures. Darcy-Weisbach is more general and works for all fluids and temperature ranges.

Darcy-Weisbach Friction Loss Calculator

Calculate head loss due to pipe friction: h_f = f·(L/D)·(V²/2g). Uses Moody chart friction factor. Supports Colebrook-White and Swamee-Jain equations for turbulent flow friction factor.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate head loss due to pipe friction: h_f = f·(L/D)·(V²/2g). Uses Moody chart friction factor. Supports Colebrook-White and Swamee-Jain equations for turbulent flow friction factor. Use the darcy-weisbach result to inform your clinical assessment.

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Frequently Asked Questions

How do I find the Darcy friction factor?

What is pipe roughness ε?

When should I use Hazen-Williams instead?