{"uid":"cap_gMV7b3ibE217aHLMlf0lV","slug":"hydrology-open-channel-calc-froude-number-153af0e5","name":"Hydrology & Open-Channel Calc – Froude Number","description":"Froude number V / sqrt(g A/T) and flow regime (subcritical, critical, supercritical) for an open-channel section.","url":"https://hydrology-calc.x402tookit.com/froude-number?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["shape","depth"],"properties":{"flow":{"type":"number","description":"Discharge in m3/s or ft3/s (send flow or velocity)"},"depth":{"type":"number","description":"Flow depth in metres or feet (circular: below the diameter)"},"shape":{"type":"string","description":"rectangular, trapezoidal, triangular or circular"},"units":{"type":"string","description":"si (default) or us"},"diameter":{"type":"number","description":"Pipe diameter in metres or feet (circular)"},"velocity":{"type":"number","description":"Mean velocity in m/s or ft/s (send velocity or flow)"},"sideSlope":{"type":"number","description":"Side slope z, horizontal run per 1 vertical (trapezoidal, triangular)"},"bottomWidth":{"type":"number","description":"Bottom width in metres or feet (rectangular, trapezoidal)"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"flow":{"type":["null","number"]},"depth":{"type":["null","number"]},"shape":{"type":["null","string"]},"units":{"type":["null","string"]},"source":{"type":["null","string"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"flowArea":{"type":["null","number"]},"topWidth":{"type":["null","number"]},"velocity":{"type":["null","number"]},"disclaimer":{"type":["null","string"]},"flowRegime":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"bottomWidth":{"type":["null","number"]},"froudeNumber":{"type":["null","number"]},"waveCelerity":{"type":["null","number"]},"hydraulicDepth":{"type":["null","number"]},"specificEnergy":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_0jWdN--91kFOdab48p3PX","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Computes the Froude number (V / sqrt(g·A/T)) and classifies the flow regime (subcritical, critical, or supercritical) for rectangular, trapezoidal, triangular, or circular open-channel sections.","exampleAgentPrompt":"What's the Froude number and flow regime for a rectangular channel that's 3 metres wide, carrying a discharge of 5 m³/s at a flow depth of 0.8 metres in SI units?","exampleUseCases":[{"title":"Drainage channel flow regime check","prompt":"I'm designing a trapezoidal drainage channel with a bottom width of 2 m, side slopes of 1.5 horizontal per 1 vertical, a flow depth of 1.2 m, and a discharge of 8 m³/s — can you tell me the Froude number and whether the flow is subcritical or supercritical?"},{"title":"Circular culvert hydraulic classification","prompt":"For a circular culvert with a 1.2-metre diameter flowing at a depth of 0.9 m and a mean velocity of 3.5 m/s in SI units, what is the Froude number and what flow regime does that correspond to?"},{"title":"US customary triangular channel analysis","prompt":"Compute the Froude number for a triangular channel with side slopes of 2 horizontal to 1 vertical, a flow depth of 2.5 feet, and a discharge of 30 ft³/s using US customary units — is the flow subcritical, critical, or supercritical?"}],"resultDescription":"Returns the computed Froude number, flow regime classification (subcritical, critical, or supercritical), cross-sectional flow area, top width, wave celerity, velocity, and a plain-language summary — plus any applicable disclaimer and degraded/not-checked flags.","failureModes":["Missing required query parameters (shape or depth) returns a 400 error","Providing neither flow nor velocity results in an error since one is required","Circular shape missing diameter parameter causes an error","Invalid shape string (not rectangular, trapezoidal, triangular, or circular) returns error","Depth exceeding pipe diameter for circular section may return a bounds error","Payment failure or insufficient USDC balance returns a 402 Payment Required response"],"whenToPreferThis":"Choose this endpoint when you need a direct, paid-per-call computation of the Froude number and flow regime for standard open-channel cross-sections (rectangular, trapezoidal, triangular, circular) without building your own hydraulic solver. It is part of a suite of hydrology tools on the same host, so prefer it alongside the Manning flow, critical depth, and normal depth endpoints for comprehensive open-channel analysis workflows.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-11-02T18:32:58.078Z","isFirstParty":false,"canonicalSlug":"hydrology-open-channel-calc-froude-number-153af0e5"}