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    "Swamee 1992 θ and (y1+15a) form; C_d is reported",
    "Drowned when y1 < 0.81 y2 (y2/a)^{0.72}",
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  "limitations": [
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    "Requires y2; drowned when y1 < 0.81 y2 (y2/a)^{0.72}; a/y1∈[0.05, 0.65]; y1>y2>a; SI",
    "Not free-flow sluice without y2, not Villemonte H1+H2 weir, not tank orifice C_d A √(2gH), not Manning n, not Q=Av"
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    "a ≥ y1 or a/y1 outside [0.05, 0.65] → VALUE_OUT_OF_RANGE",
    "y2 free-flow, H1/H2, L/H, A/v, n, given Cd → MIXED_INPUT_ENCODING",
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    {
      "title": "Swamee, P.K. Sluice-gate discharge equations",
      "section": "J. Irrig. Drain. Eng. 118(1), 1992",
      "supports": "Drowned Cd=θ·0.611[(y1−a)/(y1+15a)]^{0.072} with θ from y1, y2, a; free/drowned split y1 ≶ 0.81 y2 (y2/a)^{0.72}",
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      "url": "https://www.iso.org/standard/31895.html",
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