Verified calculation capability

Venturi meter Calculation Capability

Incompressible venturi Q=C_d A2 √(2Δp/(ρ(1−β⁴))), β=D2/D1. Default C_d=0.98. Optional same-fluid Δh. Not an orifice wrap, not Q=Av, not Darcy, not Cv/Kv. · Physics · Fluid

Capability ID physics.fluid.venturi · version 1.0.0

Open calculator REST API MCP Evidence Evidence JSON Review policy

Model

Discharge

Discharge: Q = C_d A2 √(2Δp / (ρ (1 − β⁴)))
Approach: β = D2/D1 · E = 1/√(1 − β⁴)
Manometer: Δp = ρ g Δh (same fluid)

Solve modes: flow · pressure · throat · Cd

Inputs / Outputs

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

Symbol	Quantity	Unit	Role
`D1`	Inlet diameter in m. Alias D_inlet. Not orifice pipe D.	—	input / output
`D2`	Throat diameter in m. Required except throat invert. Alias D_throat. Not orifice d.	—	input / output
`dP`	Inlet-to-throat Δp in Pa. Alternative: same-fluid dH. Do not send both.	—	input / output
`dH`	Same-fluid manometer head in m. Alternative: dP. Do not send both. Not tank H.	—	input / output
`Q`	Volumetric flow in m³/s. Required for pressure, throat, and Cd invert. Do not send with flow.	—	input / output
`rho`	Density in kg/m³. Required for Δp encoding and pressure invert. Optional when only dH is given for flow.	—	input / output
`Cd`	Discharge coefficient. Default 0.98. Do not send with Cd invert.	—	input / output
`g`	Gravity in m/s². Default 9.80665.	—	input / output
`Q_ideal`	—	—	output
`beta`	—	—	output
`E`	—	—	output
`A1`	—	—	output
`A2`	—	—	output
`v1`	—	—	output
`v2`	—	—	output
`model`	—	—	output

Assumptions / Validity

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

Assumptions

Incompressible venturi tube; SI; default C_d=0.98; C_d in (0, 1]
Q=C_d A2 √(2Δp/(ρ(1−β⁴))), β=D2/D1; Q_ideal uses C_d=1
Optional same-fluid manometer Δh with Δp=ρ g Δh; not tank H
Not an orifice plate, not Q=Av, not Darcy, not minor-loss K, not valve Cv/Kv

Not supported

orifice plate
Q=Av identities
Darcy–Weisbach
minor-loss K
valve Cv/Kv
compressible ISO ε(Re)
ISO 5167-4 C(Re)

Example

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

D1=0.1 D2=0.05 dP=10000 rho=1000 → Q=0.98 E A2 √(2Δp/ρ)

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: 17/17 calculation tests · golden 2/2 · boundary 10/10 · 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; 163 CURRENT) @ 2026-09-17T06:27:56.932Z
Semantic contract: PASS
Evidence attested at: 2026-09-17T06:27:56.176Z
Last production check: 2026-09-17T06:27:56.176Z
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. Reference Calculation Standard — Production surface contract 4/4.

Tool id: venturi
Engine: venturi
REST: POST /api/v1/calc/venturi
MCP: execute_calculation with capability_id: "physics.fluid.venturi"
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

ISO 5167-4 — Measurement of fluid flow by means of pressure differential devices — Venturi tubes — Incompressible discharge with velocity-of-approach factor
White, F.M. Fluid Mechanics — Venturi meter from Bernoulli plus continuity

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.venturi"}}}'

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