{"openapi":"3.1.0","info":{"title":"Flow Rate API","version":"1.0.0","description":"Pipe-flow maths as an API, computed locally and deterministically. The flow endpoint relates the three quantities of pipe flow — volumetric flow rate, fluid velocity and pipe diameter — through the continuity relation Q = A·v (with A = π/4·D²): give any two and it returns the third, with the flow rate expressed in litres per second and minute, cubic metres per hour, US gallons per minute and cubic feet per minute, plus the velocity and the pipe cross-section. The reynolds endpoint computes the Reynolds number from velocity, diameter and the fluid (water, air, oil and more, or a custom kinematic viscosity) and classifies the flow as laminar, transitional or turbulent. The convert endpoint converts a flow rate between litres per second and minute, cubic metres per hour, US gallons per minute, cubic feet per minute and per second. Everything is computed locally and deterministically, so it is instant and private. It is computed in SI internally; Reynolds uses the kinematic viscosity at about 20°C. Ideal for plumbing and HVAC tools, pump and irrigation sizing, process and fluid-engineering software, and hydraulics calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. 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