Source: https://guthlabs.ai/docs/instruments/reynolds-number-calculator/implementation/

instrument implementation / implementation-contract

# Reynolds Number Calculator implementation

A source-bound implementation contract for Reynolds Number Calculator; 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**: t4-216

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification leaves internal versus external classification thresholds and negative-velocity convention unspecified, and μ = 0 produces an undefined result that must be rejected rather than numerically evaluated.

## 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": {
    "flow_type": "internal_smooth_circular_pipe",
    "rho_kg_m3": 998,
    "velocity_m_s": 2,
    "characteristic_length_m": 0.05,
    "mu_Pa_s": 0.001
  },
  "expected_outputs": {
    "Re": 99800,
    "flow_regime": "turbulent"
  },
  "working": "Re=ρVL/μ=(998 kg/m³)(2 m/s)(0.05 m)/(0.001 Pa·s)=99.8/0.001=99,800. Since Re>4000, the regime is turbulent."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/reynolds-number-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/reynolds-number-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/reynolds-number-calculator/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-tranche4/tranche4-results.json`