Fluid Mechanics

Fluid mechanics calculators

Pipe flow, pressure drop, valves, pumps, orifice plates, tank draining, and Reynolds number tools for quick process-engineering checks.

When to use these calculators

Use these tools when the question is how much fluid moves, how much pressure is lost, or what pump and valve duty is implied by a line-up.

Typical workflow

1. Start with pipe velocity and Reynolds number to check the flow regime.
2. Use pipe and fittings pressure drop to estimate total system loss.
3. Size pumps, control valves, or orifice plates from the calculated flow and pressure conditions.

Calculators

• Pipe Pressure Drop Calculator — Frictional ΔP and head loss for single-phase flow in a circular pipe (Darcy–Weisbach, Swamee–Jain friction factor).
• Fittings Pressure Drop (K-factors) Calculator — Minor losses through elbows, tees, and valves by the ΣK excess-head method — the companion to straight-pipe friction.
• Pipe Velocity & Reynolds Calculator — Line velocity, Reynolds number, and flow regime from flow rate and pipe inside diameter.
• Friction Factor (Moody) Calculator — Darcy (and Fanning) friction factor from Reynolds number and relative roughness — Colebrook–White solved exactly, with the Swamee–Jain explicit fit for comparison.
• Pipe Line Sizing (velocity) Calculator — Required pipe bore for a target line velocity, with the resulting velocity and typical service velocity guidance.
• Orifice Plate Flow Calculator — Flow rate through a sharp-edged orifice plate from measured differential pressure (ISO 5167 form, incompressible).
• Tank Drain Time Calculator — Time to gravity-drain a vertical cylindrical tank through a bottom orifice or nozzle (Torricelli).
• Tank Volume Calculator — Total capacity and liquid volume at a given level for a cylindrical tank with flat, 2:1 ellipsoidal, or hemispherical heads — vertical or horizontal.
• Pump Sizing (API 610) Calculator — Hydraulic, shaft, and motor power for a centrifugal pump from flow, head, and efficiencies, with an API 610 motor-margin recommendation.
• NPSH Available Calculator — Net positive suction head available at a pump, with optional margin check against NPSH required.
• Pump Affinity Laws Calculator — Scale pump flow, head, and power to a new speed or impeller diameter using the affinity laws.
• Control Valve Cv (Liquid) Calculator — Flow coefficient (Cv and Kv) for a liquid-service control valve, with a choked-flow / cavitation check.

Other engineering domains

• Heat Transfer
• Process Safety
• Thermodynamics