9.5 KiB
Jet-circle closed-control-volume pilot
Current experimental source provenance
This development branch now includes the reviewed AMR-channel source changes originating in 5338864748ac67fe2544487c059ba149ebf916da and 47b05bc8abfc957fe876b0c63bdb386e3c6cbaa5. The current full-source manifest pins the latter reviewed source snapshot, including the new channel files. This is an explicit new experiment; neither source review nor host tests transfer historical d79 GPU/flow acceptance to it. The channel GPU gate has not yet run at integration time.
New run JSON records the source-origin pin plus checkout_revision (actual Git HEAD), checkout_dirty, and the experimental-source label. The origin pin is not claimed to be the run's checkout commit. Numerical definitions and thresholds are unchanged. Runs require a Git checkout for this runtime identity; source hash checks remain active.
Historical d79 Re100/Jet execution stays reproducible at 69e9b78de9483a5ff21e2d0c74311d240bfaf88c; the d79 LES diagnostic checkpoint is 20ae6770924df15f31305aad56e44a54a3dd4d88. Their manifests and existing result files are not rewritten. Use those commits to reproduce or interpret old d79 evidence. The current AMR-channel experiment requires its own GPU and applicable flow evidence.
Status: CPU preparation only. No GPU run or production change. Current source origin: reviewed AMR-channel snapshot 47b05bc8abfc957fe876b0c63bdb386e3c6cbaa5; this new experiment has no inherited d79 GPU acceptance. tests/validation/data/jet_circle_cv/source_manifest.json checks all tracked source file hashes before importing GPU code.
Execute only after root-owned GPU serialization
From the repository root, with REPO set to the repository root and an absent output directory:
PYTHONPATH=src python -m pytest -q tests/unit/test_jet_circle_cv.py
python tests/validation/run_jet_circle_cv.py --repo "$REPO" --output "$OUTPUT" --plan
CUDA_VISIBLE_DEVICES="$VERIFIED_IDLE_GPU" python tests/validation/run_jet_circle_cv.py --repo "$REPO" --output "$OUTPUT"
The runner does not select, reserve, or contact a GPU machine. It requires one explicit CUDA_VISIBLE_DEVICES value, at least 1 GiB free, and refuses an existing output directory. It imports existing PyCUDA; no installation. Default pilot: 800 base steps, 8 output windows, at most 1800 seconds after READY. READY is printed only after both steppers compile, execute one base/two fine warmup hops, exercise download/raw paths, and reset initial state/time. A pre-READY silence may be compilation, not stepping progress. Root owns any overall startup timeout and all launch serialization.
Physical/numerical case
Periodic root box 192 by 128, center (96,64) in root cell-edge coordinates, D=24.084, U0=.03, nu=.0072252, Re_D=100, beta=Vj/U0=.1, rho0=1. Unforced D2Q9 SRT FP32, no DDF shifting, no LES. The slightly noninteger diameter was selected solely to avoid q clipping at all three planned scales. Circle is stationary. Two uniform radial sectors at pi/2 and 3pi/2, half-width pi/12: top blows outward +.003, bottom sucks inward -.003; remaining wall has zero velocity. This periodic transient is NOT DFG, infinite-stream drag, or statistical high-Re validation. End time is t*=t U0/D approximately .9965.
AMR bounds (48,32,144,96). Finest dx=dt=.5 in root lattice units, nu_fine=2 nu, finest D=48.168. Full-domain fine reference is 384 by 256 with exactly the same finest spacing, timestep, viscosity, collision and storage. Root tau=.5216756, fine tau=.5433512, Mach approximately .05196.
AMR uses actual public FixedPatchStepper Jet construction and raw observation. The uniform blocked reference reuses the existing test_raw_exchange_gpu.py optional-input validation adapter: production Jet-derived velocity/force-arm arrays feed the unchanged blocked curved kernel. Its normal public PeriodicBlockStepper API is passive-only. This does not claim there is no uniform Jet route anywhere: Simulation.add_jet exists, but the same-blocked-kernel adapter removes a backend/storage confound for this comparison. No new public backend is introduced. Runtime asserts matching directions, q, fallback and true hit coordinates after frame conversion; both sectors must resolve links. Unclamped q/no fallback is required.
Independent measurements and signs
Two closed rectangles: (72,44,120,84) and (64,40,128,88), wholly within the finest patch. Every contour face has two active-fluid stencil layers. Capture physical postcollision populations at t=0 and every completed base interval. Collision conserves density/momentum; these are valid endpoint moments, NOT precollision stress estimates.
For each contour, M and P sum fluid-cell rho and rhou times h^2, excluding the staircase solid. Face midpoint quadrature integrates rhou dot n and [rhouu+pI-mu(grad u+grad u.T)] dot n. Velocity gradients use centered differences in root-length units, mu=rho*nu, p=(rho-1)/3. Constant pressure subtraction integrates to zero on a closed rectangle. No raw exchange enters these field quantities.
Trapezoidal time integration samples every base step over the SAME reported [step_start,step_end] as cumulative raw impulses/masses. For each window:
- mass into fluid through body surface = delta M + integral outer mass flux
- raw boundary reaction target = -delta P - integral outer momentum-minus-traction flux
Raw rows are [Jx,Jy,angular impulse,mass into fluid]; each uniform fine hop scales by [.25,.25,.125,.25], exactly as the AMR interval ledger. Both fine hops are accumulated. AMR observation time endpoints and the public raw reduction are checked. Reports separate total, wall, aperture, blowing and suction raw rows. Coefficients divide force by .5rho0U0^2*D. These are momentum reactions including aperture transport; neither raw aperture nor total raw reaction is labelled solid-only hydrodynamic traction.
Independent aperture mass estimates integrate measured rhou dot e_r over true arcs using 64-point Gauss quadrature and nearest active-fluid samples. No target velocity or raw row enters this estimate. Reports include maximum sampling distance, actual signed raw mass rates and nominal signed volume flux ±2(pi/12)RVj. Near-wall nearest-node sampling is only a first-order diagnostic, not certified wall extrapolation. Nominal volume flux is not asserted to equal measured mass flow at finite density variation.
Inventory near the circle is a staircase-cell approximation; its geometric error and face/time quadrature errors can appear in CV residuals. Two-contour spread and grid refinement are essential. No exact continuum force value, solid traction recovery, jet hardware load, or physics acceptance is claimed. Output status is deliberately PILOT_DIAGNOSTIC_ONLY even on successful execution.
Scope, refinement, resources
Default one pilot only. Estimated device envelope 128 MiB, required free 1 GiB; bounded JSON only, conservatively under 2 MiB, no population snapshots or per-step logs. Every base step downloads both fields for independent quadrature, so PCIe/CPU diagnostic cost is intentional. Six CPU tests cover descriptor/source identity, uniform flux cancellation, affine convective divergence, quadratic viscous sign/coefficient, matched geometry/Jet selection and diffusive scaling.
Optional --scale 2 or 4 doubles/quadruples all lengths and divides U,V by that scale, holds lattice nu fixed, and scales steps/windows by scale^2: physical Re and t* match, Mach decreases. Source and geometry guards repeat. Device estimate scales as scale^2; memory gate requires twice the estimate or 1 GiB, whichever is greater. Scale 4 is not part of default authorization/readiness. --re 400 requires --allow-re400 and a separate reviewed root launch decision after Re100 evidence; no automatic promotion.
Compare AMR/reference velocity error, signed reaction coefficients, each contour's independently measured reaction and residual, contour spread, signed mass budgets, and measured aperture flux. Freeze numerical tolerances only after agreeing a scientifically appropriate convergence criterion; this preparation imposes only structural/finite-state guards. A completed pilot cannot establish convergence.
Follow-on design retained: porous Couette crossflow with u=Uexpm1(Re_Vy/H)/expm1(Re_V), v=V and unequal exact wall shear. It requires validation-only planar geometry and is intentionally not implemented here.
Amplitude, geometry, and high-Re limits
Both Jet amplitudes are constant throughout the run and every fine substep; geometry is fixed. There is no runtime switch, per-step forcing schedule, or moving-wall velocity in this campaign. Construction/packing happens once, with identical uploaded amplitudes in the uniform adapter. This avoids any substep timing ambiguity from amplitude changes.
Every case records actual tau_root and tau_fine. For this fixed s=1 geometry and speed, Re400 would give nu=.0018063, tau_root=.5054189 and tau_fine=.5108378, close to the SRT limit .5. The implemented Re choices are a bounded campaign menu, not a universal physical Reynolds-number ceiling. Higher-Re evidence may require a larger initial resolved geometry or a different justified grid/relaxation design before launch. Diffusive refinement at constant lattice nu improves spatial/Mach resolution but does not move tau farther from .5; simply selecting scale=2 does not cure a poor tau. No all-Re, LES or three-dimensional realism claim follows from this pilot.
The source guard checks production file content against the current reviewed source origin, not validation-branch HEAD. This runner is validation-only; generated results and frozen execution-package archives are not committed.