ClaudeandClaude Opus 5.5
2220cdd157
Per review ofaceea70e: a dirty checkout is refused (HEAD would not describe the code that runs, and a dirty-to-dirty edit would pass the end-of-run check). On a clean tree HEAD pins the imported helpers too. plan.json and result.json carry schema=2; schema-1 receipts (bare list, e.g. evidence70f6617) are documented. Adds a dirty-refusal test. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
53 lines
2.9 KiB
Markdown
53 lines
2.9 KiB
Markdown
# DFG 2D-1 (Re 20) against the official reference intervals
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`tests/validation/run_dfg_re20.py` runs the steady DFG 2D-1 case on the refined
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channel root (D40 root, D80 wide fine patch) and on the uniform D80 grid. Geometry,
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inflow, initial state, layout and observation are those of the pinned Re100 runner
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(`run_refined_dfg.py`, `re100_helpers.py`, both unchanged); only the lattice
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viscosity is set for Re 20 (root tau 0.56, fine 0.62, uniform 0.62, lattice speed 0.01).
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Label: "compared against the official reference bands", not a full benchmark
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certification: the outlet is pressure-NEQ (`neq_extrap`), not do-nothing, and the
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inlet is local Zou-He.
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## Quantities
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- Cd = 2 Fx / (rho U^2 D), Cl = 2 Fy / (rho U^2 D), interval means over each sample.
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- p_diff = p(0.15, 0.2) - p(0.25, 0.2), linear extrapolation to the exact surface
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points (`re100_helpers.pressure_probes`). The helper returns dp / (rho U^2) in
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scaled units; p_diff = dp * 0.04 for U = 0.2 m/s, rho = 1. Both are reported.
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- Official intervals (Schaefer & Turek 1996): Cd [5.57, 5.59], Cl [0.0104, 0.0110],
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p_diff [0.1172, 0.1176].
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## Bounds and steady rule (frozen before any run)
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- End time t* = 60 (30 s physical): 240,000 refined root steps, 480,000 uniform steps.
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- One sample every t* = 0.5 (0.25 s) at the end of a synchronized root step; Cd and
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Cl are interval means. Trailing window t* 50..60 inclusive (21 samples).
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- Steady rule (our engineering choice, not official): in the window, for each of Cd,
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Cl, p_diff, max - min <= 10 % and |least-squares slope x window| <= 2 % of its
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official interval width (range 2e-3 / 6e-5 / 4e-5; slope 4e-4 / 1.2e-5 / 8e-6).
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Absolute limits, so the small Cl is never a divisor. Never relaxed after a run.
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- The verdict uses the window mean; the distance to the nearest interval edge is
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reported for each quantity (negative outside).
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- Force sign: fluid on cylinder, x along the inflow, y up from the bottom wall; Cd > 0
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and the official Cl > 0 (`cd_positive` is reported).
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- Not steady at t* = 60: status `NOT_STEADY`, no interval verdict. Health limits
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(Mach <= 0.2, rho in [0.5, 1.5]) stop the run with `UNHEALTHY`.
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- Steady: `WITHIN_INTERVALS` or `OUTSIDE_INTERVALS`, with the per-quantity verdict.
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## Run
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```
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python tests/validation/run_dfg_re20.py --output <new-dir> --plan
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CUDA_VISIBLE_DEVICES=<n> python tests/validation/run_dfg_re20.py --case both \
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--collision SRT --output <new-dir> --max-wall-seconds <cap>
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```
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The uniform D80 control separates method error from refinement error. `--plan` writes `plan.json` only. A GPU run writes `plan.json` and `result.json`
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(per case: lattice parameters, every sample, window ranges, status, verdict).
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Receipts: `plan.json` and `result.json` carry `schema` 2 and `provenance` (HEAD, src tree,
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runner hash; clean checkout required, refused if it changes during the run). Receipts
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written before this (schema 1, e.g. evidence 70f6617) are a bare list of cases.
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Host contract tests: `tests/unit/test_dfg_re20.py`.
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