Colebrook-White / Moody Friction Factor Solver implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t6-035

Effect

Computation or source lookup only

Input and validation requirements

The Re = 0 input makes both the laminar formula and the Colebrook term undefined and must be rejected. In addition, the specification does not state the laminar/transitional/turbulent thresholds or how the transitional interval is handled, and it does not explicitly distinguish Darcy from Fanning conventions beyond the equation itself.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "Re": 2000,
    "relative_roughness": "0.001",
    "method": "laminar",
    "newton_tolerance": 1e-10
  },
  "expected_outputs": {
    "friction_factor": 0.032,
    "flow_regime": "laminar"
  },
  "working": "Re=2000<2300, so use f=64/Re. 64/2000=0.032 exactly. The roughness is ignored for the laminar formula."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche6/tranche6-results.json