Source: https://guthlabs.ai/docs/instruments/normal-shock-relations-calculator/implementation/

instrument implementation / implementation-contract

# Normal Shock Relations Calculator implementation

A source-bound implementation contract for Normal Shock Relations Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_WITH_ERRATA**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-with-binding-errata

**Evidence ID**: t5-086

**Effect**: Computation or source lookup only

## Input and validation requirements

The calculator breaks or must reject several edge inputs: the exact M1=1 boundary violates the strict validity condition, gamma=1 and M1=0 causes a zero denominator and undefined results, and a subsonic input produces formal algebraic values despite being outside the normal-shock branch. Signed Mach-number handling is also convention-dependent.

## Required corrections

````
[
  {
    "vector": 2,
    "field": "T2_T1",
    "wrong": 1.0641115702,
    "correct": 1.0649380165,
    "cause": "T2/T1 must equal her own correct P2/P1 ÷ rho2/rho1 (1.245/1.169082)"
  }
]
````

## Inspectable interface fixture

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

````
{
  "inputs": {
    "M1": 2,
    "gamma": 1.4
  },
  "expected_outputs": {
    "M2": 0.5773502692,
    "P2_P1": 4.5,
    "T2_T1": 1.6875,
    "rho2_rho1": 2.6666666667,
    "P02_P01": 0.7208738615
  },
  "working": "M1²=2²=4. M2²=(1+((1.4-1)/2)×4)/(1.4×4-(1.4-1)/2)=(1+0.2×4)/(5.6-0.2)=1.8/5.4=1/3, so M2=√(1/3)=0.5773502692. P2/P1=1+[2×1.4/(1.4+1)]×(4-1)=1+(2.8/2.4)×3=1+3.5=4.5. rho2/rho1=((1.4+1)×4)/((1.4-1)×4+2)=9.6/3.6=2.6666666667. T2/T1=4.5/2.6666666667=1.6875. P02/P01=(2.6666666667)^3.5×(2.4/10.8)^2.5=0.7208738615."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/normal-shock-relations-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/normal-shock-relations-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/normal-shock-relations-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-tranche5/tranche5-results.json`

- `tranche errata record`