Verified calculation capability

Cutthroat flume Calculation Capability

Skogerboe cutthroat free-flow Q from throat W, independent length L_f, and gage Ha. Not Parshall, not thin-plate weir, not broad-crested weir, not Manning, not Q=Av, not orifice. · Physics · Fluid

Capability ID physics.fluid.cutthroat_flume · version 1.0.0

Open calculator REST API MCP Evidence Evidence JSON Review policy

Model

Skogerboe free flow

Skogerboe free flow: Q_cfs = C Ha_ft^n
Coefficient: C = 3.50 W_ft^{1.025} (L_f / 3 ft)^{0.020}
Exponent: n = 1.56 (L_f / 3 ft)^{0.026}

Solve modes: flow · head

Inputs / Outputs

Canonical symbols for this capability. Agent schemas remain the contract.

Symbol	Quantity	Unit	Role
`W`	Throat width in m. Required. Envelope [0.0508, 1.8288] and W < L_f. Alternatives: W_m, throat, throat_width. Do not send weir b.	—	input / output
`L_f`	Independent flume length in m. Required. Envelope [0.4572, 2.7432]. Alternatives: Lf, L_flume, flume_length, length. Do not send thin-plate crest L.	—	input / output
`Ha`	Specified-gage upstream head in m. Required for flow. Envelope [0.03048, 1.2192]. Alternatives: H_a, h_a, Ha_m. Do not send weir H.	—	input / output
`Q`	Volume flow in m³/s. Required for head invert. Alternatives: flow, Q_m3_s.	—	input / output
`n`	amount of substance	—	output
`C`	—	—	output
`model`	—	—	output

Assumptions / Validity

Declared scope for this capability. Do not use it outside this domain.

Assumptions

Skogerboe cutthroat free flow: Q_cfs = C Ha_ft^n; C=3.50 W_ft^{1.025} (L_f/3 ft)^{0.020}; n=1.56 (L_f/3 ft)^{0.026}; SI W, L_f, Ha, Q; C and n are reported, not inputs
No diverging section; L_f is independent flume length, not weir crest L; W < L_f; L_f∈[0.4572 m, 2.7432 m]; W∈[0.0508 m, 1.8288 m]; Ha∈[0.03048 m, 1.2192 m]
Not Parshall 4 W_ft Ha^{1.522 W^{0.026}}, not thin-plate weir, not broad-crested (2/3)^{3/2} √g, not Manning n, not Q=Av, not orifice, not submerged Hb

Not supported

Parshall (no independent L_f)
thin-plate weir
broad-crested weir
Manning n
Q=Av
orifice
submerged Hb/Ha

Example

One numerical check. The calculator page holds worked steps and FAQ.

L_f=0.9144 W=0.3048 Ha=0.3048 → Q≈0.09911

Open this example in the calculator

Trust

Review-policy: engine tested — automated tests, sources, version lock, and evidence published. Supplemental to CVP; not Domain Expert Review. See CVP and Review policy.

Tier: Engine tested — catalog token engine_tested
Calculation version: 1.0.0
Evidence tests: 5/5 calculation tests · golden 0/0 · boundary 0/0 · property 5/5
Engine tested: Yes
Source checked: Yes
Supplemental domain review: Not performed
Named expert review: Not performed
Version lock: Supported (409 VERSION_MISMATCH)
Artifact consistency: Build verified · 1.0.0 (workspace artifacts agree)

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; 164 CURRENT) @ 2026-09-18T02:44:05.986Z
Semantic contract: PASS
Evidence attested at: 2026-09-18T02:44:05.231Z
Last production check: 2026-09-18T02:44:05.231Z
Public / cache: PASS
Origin: PASS

Call this capability

Human page, REST, and MCP share the same engine and calculation_version. Build verified hashes workspace artifacts only. After deploy, attest:production GETs canonical URLs twice — the public/cached view an Agent actually hits, and origin — including every /capabilities/{id} HTML page. Public Capability HTML version must match catalog before production attestation passes. Live Trust rows above fetch /.well-known/calculatorx-production-attestation.json and the output schema const. Build hashes: release integrity. That proves currently published page / engine / schema / evidence / MCP agree — not that a historical version is independently immutable. Production surface contract 1/1.

Tool id: cutthroat-flume
Engine: cutthroat-flume
REST: POST /api/v1/calc/cutthroat-flume
MCP: execute_calculation with capability_id: "physics.fluid.cutthroat_flume"
Agent input schema: Canonical (MCP / Agent)
Output schema: JSON Schema (latest)
Versioned input schema: Immutable pin (1.0.0)
Versioned output schema: Immutable pin (1.0.0)

References

Human-readable sources plus CVP reference evidence classes.

Sources

Skogerboe, G.V.; Hyatt, M.L.; England, J.D.; Johnson, J.R. — Design and Calibration of Submerged Open Channel Flow Measurement Structures, Part 3: Cutthroat Flumes — 3-ft family free-flow rating
ISO 80000-4 — Mechanics — Volume flow rate

Try with an agent

Inspect this capability via same-origin MCP, then call execute_calculation.

curl -sS -X POST 'https://www.calculatorx.com/mcp' \
  -H 'Content-Type: application/json' \
  -H 'MCP-Protocol-Version: 2026-07-28' \
  -H 'Mcp-Method: tools/call' \
  -H 'Mcp-Name: inspect_capability' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"inspect_capability","arguments":{"capability_id":"physics.fluid.cutthroat_flume"}}}'

Inspect the trust tier and required assurance level before execution. Pin calculation_version (1.0.0) when reproducibility matters. Full protocol notes: MCP docs.