Public evidence

physics.fluid.chezy

Machine-checked verification for calculation version 1.0.0 · tier engine_tested

Open calculator API Capability Download JSON MCP Review policy

Verification

17/17 calculation tests · Production surface contract 3/3

Golden tests 2 / 2
Boundary tests 10 / 10
Property tests 5 / 5
Production surface contract 3 / 3
Engine tested Yes
Source checked Yes
Artifact integrity PASS
Production attestation Embedded snapshot: STALE · Last attested schema matched 1.0.0 snapshot / local build · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · Public/cache ✓ · Origin ✓ · Live production status PASS (0 stale; 163 CURRENT) @ 2026-09-17T09:03:11.906Z
Semantic contract PASS
Evidence attested at 2026-09-17T09:03:11.074Z
Last production check 2026-09-17T09:03:11.074Z
Public / cache PASS
Origin PASS
Supplemental domain review Not performed
Named expert review Not performed

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS

Fingerprint sha256:e7aca832e10de5dac46a613e4cad54d344e81ba3f3b56f66e111f9b7880fc4ba

Input schema sha256:a6e6387fdc8ee3a14e970a5c7fc3d2f5ff2a30befa7ceda00dc9c4df67d82b85 · Output schema sha256:d4ba08efdb93225367c70ff8df5625dedd5542f87839814d7348c54a7d929fef · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: chezy-formula
Engine: chezy-formula
Engine build: 2026-09-17
Evidence core: 2026-09-17T06:42:15.154Z
Rendered: 2026-09-17T08:49:50.937Z
Last reviewed: —

Assumptions

Uniform open-channel flow; V = C √(R S)
C is Chezy C, not Manning n, not Hazen–Williams pipe C
Not Q=Av, not Darcy, not a weir, not Manning

Limitations

Open-channel Chezy: V = C √(R S); C is Chezy C, not Manning n, not Hazen–Williams C
Uniform flow; R is hydraulic radius; S is friction slope
Not Manning, not Q=Av, not Darcy, not Hazen–Williams, not a weir

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

ISO 80000-4 — Mechanics — Volume flow rate and hydraulic radius
Supports: Hydraulic radius R is a length; mean velocity is length per time
Chow, V.T. Open-Channel Hydraulics — Chezy formula
Supports: Uniform-flow Chezy V = C √(R S); Manning is a later roughness encoding of C

Published checks

Golden, boundary, and property cases included in this evidence build.

ID	Kind	Status	Detail
`golden-ch-v`	golden	pass	Expected v=1.5811388300841895 · C=50 · R=1 · S=0.001 · mode=velocity · model=chezy · Actual mode=velocity · v=1.5811388300841895 · C=50 · R=1 · S=0.001 · model=chezy
`golden-ch-C`	golden	pass	Expected C=50 · model=chezy · Actual mode=C · v=1.5811388300841895 · C=50 · R=1 · S=0.001 · model=chezy
`boundary-ch-R`	boundary	pass	Expected R=1 · model=chezy · Actual mode=R · v=1.5811388300841895 · C=50 · R=0.9999999999999998 · S=0.001 · model=chezy
`boundary-ch-S`	boundary	pass	Expected S=0.001 · model=chezy · Actual mode=S · v=1.5811388300841895 · C=50 · R=1 · S=0.0009999999999999998 · model=chezy
`boundary-ch-missing`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-ch-c0`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-ch-n`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-ch-A`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-ch-D`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-ch-manning`	boundary	pass	Expected INVALID_MODE · Actual INVALID_MODE
`boundary-ch-K`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`boundary-ch-f`	boundary	pass	Expected MIXED_INPUT_ENCODING · Actual MIXED_INPUT_ENCODING
`property-ch-v`	property	pass	V=C √(R S)
`property-ch-roundtrip-C`	property	pass	C invert
`property-ch-roundtrip-R`	property	pass	R invert
`property-ch-roundtrip-S`	property	pass	S invert
`property-ch-model`	property	pass	chezy