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  "internally_reviewed": false,
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      "sources",
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  "assumptions": [
    "Joukowsky water hammer: Δp = ρ c Δv; h = Δp/(ρ g); default ρ=1000 kg/m³; default g=9.80665 m/s²",
    "c is the given celerity, not Moens–Korteweg from bulk modulus K, D, e, E",
    "Not Darcy f, not Colebrook, not minor-loss K, not Q=Av"
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  "limitations": [
    "Joukowsky water hammer: Δp = ρ c Δv; h = Δp/(ρ g); default ρ=1000 kg/m³; default g=9.80665 m/s²",
    "c is the given celerity, not Moens–Korteweg from bulk modulus K, D, e, E",
    "Not Darcy f, not Colebrook, not minor-loss K, not Q=Av"
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  "boundary_conditions": [
    "missing c, Δv, or Δp when required → MISSING_REQUIRED_INPUT",
    "c, Δv, Δp, ρ, or g ≤ 0 → VALUE_MUST_BE_POSITIVE",
    "f/Re, K, L/D/e/E, n, A/Q, v → MIXED_INPUT_ENCODING",
    "darcy, minor, or manning as mode → INVALID_MODE"
  ],
  "sources": [
    {
      "title": "ISO 80000-4 — Mechanics",
      "section": "Pressure, density, speed",
      "supports": "Δp is a pressure; ρ is a density; c and Δv are speeds",
      "kind": "standard"
    },
    {
      "title": "Wylie, E.B. and Streeter, V.L. Fluid Transients",
      "section": "Joukowsky equation",
      "supports": "Δp = ρ c Δv for a rapid velocity change in a liquid-filled pipe",
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        "dV": 1
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        "c": 1000,
        "dV": 1,
        "rho": 1000,
        "mode": "pressure",
        "model": "joukowsky"
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        "dP": 1000000,
        "rho": 1000,
        "c": 1000,
        "dV": 1,
        "h": 101.97162129779282,
        "g": 9.80665,
        "model": "joukowsky"
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        "model": "joukowsky"
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        "dP": 1000000,
        "rho": 1000,
        "c": 1000,
        "dV": 1,
        "h": 101.97162129779282,
        "g": 9.80665,
        "model": "joukowsky"
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        "dP": 1000000,
        "dV": 1
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        "model": "joukowsky"
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        "mode": "celerity",
        "dP": 1000000,
        "rho": 1000,
        "c": 1000,
        "dV": 1,
        "h": 101.97162129779282,
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        "model": "joukowsky"
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      "ok": true,
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      "code": "MISSING_REQUIRED_INPUT",
      "error": "dV is required"
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      "id": "boundary-wh-f",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "f": 0.02
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      "expectError": "MIXED_INPUT_ENCODING",
      "code": "MIXED_INPUT_ENCODING",
      "error": "Water hammer does not take Darcy f, Re, or roughness. That is /calc/physics/darcy-weisbach or /calc/physics/colebrook"
    },
    {
      "id": "boundary-wh-K",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "K": 0.5
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      "expectError": "MIXED_INPUT_ENCODING",
      "code": "MIXED_INPUT_ENCODING",
      "error": "Water hammer does not take minor-loss K or bulk modulus K. Give celerity c. Wave speed is /calc/physics/wave-celerity; fitting K is /calc/physics/minor-loss"
    },
    {
      "id": "boundary-wh-L",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "L": 100
      },
      "expectError": "MIXED_INPUT_ENCODING",
      "code": "MIXED_INPUT_ENCODING",
      "error": "Water hammer does not take L, D, wall e, or E. Give c; wave speed from K, D, e, E is /calc/physics/wave-celerity"
    },
    {
      "id": "boundary-wh-A",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "A": 1
      },
      "expectError": "MIXED_INPUT_ENCODING",
      "code": "MIXED_INPUT_ENCODING",
      "error": "Water hammer does not take Q=Av A/Q. Use Δv, not Q"
    },
    {
      "id": "boundary-wh-n",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "n": 0.013
      },
      "expectError": "MIXED_INPUT_ENCODING",
      "code": "MIXED_INPUT_ENCODING",
      "error": "Water hammer does not take Manning n or Chezy C/R/S"
    },
    {
      "id": "boundary-wh-v",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "v": 1
      },
      "expectError": "MIXED_INPUT_ENCODING",
      "code": "MIXED_INPUT_ENCODING",
      "error": "Water hammer uses dV, not v. That is /calc/physics/pitot-tube or /calc/physics/froude-number"
    },
    {
      "id": "boundary-wh-darcy",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 1,
        "mode": "darcy"
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      "expectError": "INVALID_MODE",
      "code": "INVALID_MODE",
      "error": "mode must be pressure|velocity|celerity. Not Darcy, minor-loss, Manning, or Q=Av"
    },
    {
      "id": "boundary-wh-zero",
      "ok": true,
      "kind": "boundary",
      "inputs": {
        "c": 1000,
        "dV": 0
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      "ok": true,
      "kind": "property",
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