Source: https://guthlabs.ai/docs/instruments/pipe-duct-reynolds-number-flow-regime/implementation/

instrument implementation / implementation-contract

# Pipe/Duct Reynolds Number & Flow Regime implementation

A source-bound implementation contract for Pipe/Duct Reynolds Number & Flow Regime; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## 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**: t5-161

**Effect**: Computation or source lookup only

## Input and validation requirements

The zero-viscosity vector produces an undefined Reynolds number and requires rejection; accepting it and returning a finite value or a regime would be erroneous. The specification also leaves regime thresholds and signed-velocity convention unstated.

## 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": {
    "rho_kg_m3": 998,
    "V_m_s": 2,
    "D_m": 0.05,
    "mu_Pa_s": 0.001
  },
  "expected_outputs": {
    "Re": 99800,
    "flow_regime": "turbulent"
  },
  "working": "Re = ρVD/μ = (998 kg/m³ × 2 m/s × 0.05 m) / 0.001 Pa·s. First, 2 × 0.05 = 0.1. Then, 998 × 0.1 = 99.8. Finally, 99.8 / 0.001 = 99,800. Since 99,800 > 4,000, the regime is turbulent."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/pipe-duct-reynolds-number-flow-regime/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/pipe-duct-reynolds-number-flow-regime/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/pipe-duct-reynolds-number-flow-regime/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`