Conner Majic
725a72a773
Set up the C solver core, Node API orchestration, TS GUI workflow, and engineering documentation with cleaned repo hygiene for private Git hosting. Made-with: Cursor
47 lines
1.5 KiB
Markdown
47 lines
1.5 KiB
Markdown
# Units and internal conventions
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Owner: Rods Project Team
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Status: Active
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Last Updated: 2026-04-16
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## Principle
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All values passed from `solver-api` to `solver-c` **JSON** are **SI**:
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| Quantity | SI unit |
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|----------|---------|
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| Length | m |
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| Force | N |
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| Pressure | Pa |
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| Mass density | kg/m³ |
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| Time | s |
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| Angle | rad (stored in JSON as rad; XML may be degrees) |
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| SPM | 1/min (dimensionally s⁻¹ scale; kept as `pumping_speed` scalar per stroke period \(T = 60/\text{SPM}\) s) |
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## `UnitsSelection` (XML)
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`base-case.xml` uses `<UnitsSelection>2</UnitsSelection>` (example). Parser maps:
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| Code | Assumption in parser |
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|------|----------------------|
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| `0` / missing | Field units match legacy **oilfield mixed** inch–ft–lbf where applicable (see below) |
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| `2` | **Imperial oilfield** — lengths in **ft**, diameters in **in**, moduli in **Mpsi** (×10⁶ psi), forces in **lbf**, pressures in **psi** |
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| Other | Treated like `2` with warning in `parsed.warnings` (`heuristic`) |
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### Conversion factors (exact)
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- `1 in = 0.0254 m`
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- `1 ft = 0.3048 m`
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- `1 lbf = 4.4482216152605 N`
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- `1 psi = 6894.757293168 Pa`
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- `1 Mpsi = 6.894757293168e9 Pa`
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- `deg → rad`: multiply by \(\pi/180\)
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### Fluid density helper
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Mixture density from `WaterCut`, `WaterSpecGravity`, `FluidLevelOilGravity` uses simplified API formula for buoyancy; tagged `heuristic` in `model.fluidDensityHeuristic`.
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## JSON to C
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`SolverInputs` receives only SI. GUI may show field units; API documentation states SI in solve payload.
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