Source: https://guthlabs.ai/docs/instruments/deep-water-wave-speed-period/

instrument / verified-clean

# Deep-Water Wave Speed & Period

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/deep-water-wave-speed-period/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/deep-water-wave-speed-period/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/deep-water-wave-speed-period/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/deep-water-wave-speed-period/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Earth & Space (astronomy, orbital mechanics, meteorology, geology, geodesy, oceanography)

**Tranche**: tranche-5

**Evidence ID**: t5-127

**Ledger rows**: 1

No ledger note is attached.

## Review findings

The formulas are correct for deep-water linear wave theory with period input and SI units. The product should not claim to accept wavelength input until the missing inverse formulas and unit behavior are specified. The honest label should clearly state that the approximation is not valid for shallow or intermediate water and that depth applicability is not currently validated.

### Formula and scope findings

- The supplied formulas are standard deep-water linear wave-theory formulas when period T is the input: c = gT/(2π), L = cT, and c_g = c/2.

- The input description says 'wave period (or wavelength)', but no wavelength-input formula is supplied. For wavelength input, the corresponding deep-water formulas would be c = sqrt(gL/(2π)) and T = sqrt(2πL/g).

- The instrument has no depth input, so it cannot verify the stated applicability condition depth > L/2 for the calculated wavelength.

### Unit assumptions

- Wave period T is in seconds unless explicitly converted before calculation.

- Wavelength L is in metres, phase speed c is in metres per second, group velocity c_g is in metres per second, and gravitational acceleration g is in metres per second squared.

- Standard gravity g = 9.80665 m/s² is assumed.

- π = 3.141592653589793 is assumed.

- The deep-water approximation is assumed valid only when water depth exceeds half the wavelength, as stated by the honest label.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

The literal plain-arithmetic implementation overflows at a period of 1e308 s even though the phase-speed expression can be algebraically rearranged to produce a finite value; it also lacks a supplied non-deep-water branch and does not define handling for negative periods.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "period_s": 6,
    "g_m_s2": 9.80665
  },
  "expected_outputs": {
    "phase_speed_m_s": 9.364660936,
    "wavelength_m": 56.187965616,
    "group_velocity_m_s": 4.682330468
  },
  "working": "c = gT/(2π) = (9.80665 × 6)/(2 × 3.141592653589793) = 58.8399/6.283185307179586 = 9.364660936 m/s. L = cT = 9.364660936 × 6 = 56.187965616 m. c_g = c/2 = 9.364660936/2 = 4.682330468 m/s."
}
````

## Related workflows

No source-defined multi-instrument workflow membership is recorded.

## Sources and evidence

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

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

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

- `BOUNDARY_HAZARD_CATALOG.json`