Convection Coefficient (Nu Correlation) Estimator 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

t7-053

Effect

Computation or source lookup only

Input and validation requirements

The zero-characteristic-length input produces h=0/0 and must be rejected. The signed-velocity probe also exposes an implementation hazard: directly raising negative Re to the fractional power 0.8 produces an undefined real-valued result, so velocity magnitude handling must be explicit.

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": {
    "geometry": "flat_plate",
    "fluid": "air",
    "temperature_C": 20,
    "velocity_m_per_s": 10,
    "characteristic_length_m": 0.5,
    "correlation": "local laminar flat plate",
    "property_reference_temperature": "20 C"
  },
  "expected_outputs": {
    "Re": 332005.31,
    "Pr": 0.707,
    "Nu": 340.84,
    "h_W_per_m2_K": 17.52
  },
  "reference_data": {
    "temperature_C": 20,
    "air_kinematic_viscosity_m2_per_s": 0.00001506,
    "air_thermal_conductivity_W_per_m_K": 0.0257,
    "air_Prandtl_number": 0.707,
    "source_convention": "widely tabulated standard value; Incropera heat-transfer textbook air-properties table"
  },
  "working": "Re=VL/nu=(10 m/s)(0.5 m)/(1.506e-5 m^2/s)=5/(1.506e-5)=332005.31. sqrt(Re)=sqrt(332005.31)=576.20. Pr^(1/3)=0.707^(1/3)=0.89085. Nu=0.664(576.20)(0.89085)=340.84. h=Nu*k/L=(340.84)(0.0257 W/(m*K))/(0.5 m)=17.52 W/(m^2*K)."
}

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-tranche7/tranche7-results.json