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CVP verified calculation capability

Colebrook Friction Factor Calculation Capability

Colebrook–White Darcy friction factor f from Re and ε/D. Turbulent pipes Re≥4000. Not laminar 64/Re.

Physics · Fluid Capability ID physics.fluid.colebrook version 1.0.0 CVP VERIFIED CURRENT Engineering

Model

Colebrook–White

Inputs / Outputs

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

SymbolQuantityUnitRole
ReReynolds number—input / output
rel_roughnessRelative roughness ε/D—input / output
epsAbsolute roughness ε in metresminput
DPipe diameter in metresminput
f——output
inv_sqrt_f——output
model——output

Assumptions / Validity

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

Assumptions

Not supported

Example

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

Re=1e5 rel_roughness=0.0002 → f≈0.019005

Open this example in the calculator

Trust

CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance · Colebrook–White turbulent f from Re and ε/D; + O3 tabulated f.. Computational verification is defined by CVP. Supplemental domain review (internal) and named expert review are defined by the Review policy and do not by themselves determine CVP conformance.

CVP
CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance · Colebrook–White turbulent f from Re and ε/D; + O3 tabulated f.· View Manifest · CVP overview · Specification
Verified scope
Colebrook–White turbulent f from Re and ε/D; + O3 tabulated f.
Assurance
Engineering
Declared partition coverage
PASS · 5/5 declared partitions (friction, smooth, awkward, boundary, invalid-domain)
Deferred
Not Darcy hf from given f, not laminar 64/Re, and not Swamee–Jain as the product.
Calculation version
1.0.0
Verification
9/9 calculation tests · 1/1 legacy golden · 5/5 legacy boundary · 3/3 legacy property
Production surface contract
6/6
Versions
Calculation 1.0.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-26.o2-o3.cov.iut
Verification revision
2026-09-26.o2-o3.cov.iut · 1/1 property · digest c54ce22c5aa4
Reference
O1 model · O3 expected_values · O3 numerical_behavior · O2 expected_values · O2 numerical_behavior
Numerical scope
O2: Colebrook–White 1/√f = −2 log10(ε/D/3.7 + 2.51/(Re√f)) via Haaland start + Newton on √f (≤2 ULP). Not Darcy hf, not laminar 64/Re, and not Swamee–Jain as the product. ≤2 ULP vs O3 applies only to the published tabulated Colebrook vectors. Not Darcy hf and not laminar 64/Re.
Interfaces
PASS · UI (SSR) / REST / MCP
ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only.
CVP suite
5/5 golden · 6/6 CVP boundary · 5/5 invalid · 1/1 property · 1/1 metamorphic · 8/8 O3 · 2/2 cross-interface · 6/6 CVP contract
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)
Review-policy tier
Engine tested — catalog token engine_tested; supplemental; not CVP status
This calculator CURRENT · Public schema 1.0.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

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 6/6.

curl -sS -X POST 'https://www.calculatorx.com/api/v1/calc/colebrook' \
  -H 'Content-Type: application/json' \
  -d '{"inputs":{"Re":100000,"rel_roughness":0.0002},"calculation_version":"1.0.0"}'

POST /api/v1/calc/colebrook. This is a POST calculate endpoint — do not GET it.

Full REST contract: REST API docs.

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

Reference evidence classes: O1 model · O3 expected_values · O3 numerical_behavior · O2 expected_values · O2 numerical_behavior

Try with an agent

Inspect, then execute. Same engine as REST and the human calculator.

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.colebrook"},"_meta":{"io.modelcontextprotocol/protocolVersion":"2026-07-28","io.modelcontextprotocol/clientInfo":{"name":"calculatorx-docs-example","version":"1.0.0"},"io.modelcontextprotocol/clientCapabilities":{}}}}'

Pin calculation_version (1.0.0) when the result must stay reproducible.

Inspect the trust tier and required assurance level before execution. Full protocol notes: MCP docs.