3 Commits

Include renames

Author	SHA1	Message	Date
Omar SobhandClaude Fable 5	35b2b2cdf4	rtx-cfd: TVD convection in the embedded predictor — the wake sheds — and Turek–Hron CFD2/CFD3 ... First-order upwind's numerical viscosity |u| h / 2 is ~10x the physical viscosity on the Turek–Hron grids: the effective Reynolds number lands near 20 and CFD3 (Re 200) produced NO vortex shedding at all — one lift zero-crossing in three seconds at h = 10 mm. The physics, not a bug. EmbeddedParameters gains `convection_scheme` (default Upwind, bit- identical — the no-body degeneracy test still reads 0.0): the TVD branch adds SIMPLE's limited face corrections (van Albada / van Leer, `face_correction` now pub(crate)) directly in the explicit predictor — no deferred iteration needed in an explicit step. Domain-side faces and faces whose far-upwind node is outside fall back to upwind exactly as in SIMPLE; near the body the stencil reads ghost values, which encode the wall. Verified: the embedded-circle MMS error drops 10–16x below upwind (8.16e-4 vs 8.49e-3 at n = 32) at observed order 1.56 (SIMPLE's TVD measured 1.59–1.84). tests/turek_hron_cfd23.rs — CFD2 (Re 100, steady) and CFD3 (Re 200, periodic), both with the benchmark's inflow ramp, both measured as time statistics over a window (never a snapshot), surface route primary and the control volume printed as the diagnostic (its central-difference evaluation truncation grows with the convective flux: the routes agree to 0.6% at Re 20 and differ 15–25% at Re 100–200 on these grids). Measured across h = 10 / 6.6 / 5 mm: - CFD3 shedding frequency 4.2746 / 4.3400 / 4.3939 Hz vs the reference 4.3956 — converging −2.8% -> −1.3% -> −0.04%; - CFD3 lift mean −184 / +160 / −2.6 vs −11.9 — lands on the reference; lift amplitude ±438 / ±556 / ±557 vs ±437.8 — +27% at the finer grids, unconverged (the flag is 2/3/4 cells thick); - CFD2 control-volume drag 152.4 / 143.3 / 139.4 vs 136.700 — +2.0% at 5 mm; CFD2 surface drag sits ~−10% (the boundary layer is ~one cell); CFD2 lift −3.4 / +30.2 / +8.4 vs 10.53. Suite defaults run CFD2 at ny = 62 and CFD3 at ny = 41 (cost); the asserted bands are the measured ones (frequency 10%, mean drag 15%, amplitude 35%), not accuracy claims; RTX_CFD2_NY / RTX_CFD3_NY run the studies. Also recorded: the CFD1 refinement study extended to h = 3.3 mm (RTX_CFD1_NY): control-volume drag 14.8996 (+4.25%), apparent order ~0.70 sustained over four grids, control-volume lift 1.1332 vs 1.11905 (+1.3%). rtx-cfd 318 -> 321 green (full suite 321 passed / 0 failed). Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 11:37:04 -07:00
Omar SobhandClaude Fable 5	327da7ff47	rtx-cfd: multigrid-PCG projection — 30x faster, same answers — and the CFD1 refinement study ... Falsifier 4 of the Turek–Hron geometry decision fired (the SOR projection cost 0.09 s/step at 250x41 and an hour per run at 5 mm); this answers it. solvers::incompressible::poisson: PoissonProblem (cell-centred five-point SPD operator as per-cell face coefficients + Dirichlet diagonal extra + active mask) and solve_multigrid_pcg — conjugate gradient preconditioned by one V-cycle of geometric multigrid: aggregation by 2 per direction (odd sizes absorbed, coarse cell active iff any child is), the Galerkin coarse operator for piecewise-constant prolongation / summation restriction, symmetric Gauss–Seidel smoothing, coarse correction scaled by 2 (Braess's under-correction of unsmoothed aggregation; scalar, so the preconditioner stays symmetric and positive on range(A)), L1 TRUE-residual stop with a stagnation guard. Singular systems are handled per connected component of the active cells (mean projection and level per pure-Neumann component; the anchor's component to p[anchor] = 0). PoissonSolverKind::{Sor, Multigrid} on PisoParameters / EmbeddedParameters; Sor is the default and its code is byte-for-byte untouched; an unconverged multigrid solve falls back to the SOR sweeps for that projection. Verified (poisson/tests.rs, tests/poisson_equivalence.rs): - PCG iterations to cut the residual 1e-8 on the closed Neumann box at 32^2..256^2: 4, 4, 4, 4; ragged masked domains 8/8/8; - manufactured recoveries to ~1e-14; Galerkin identity A_c v = R A P v to 7e-15 on every level (masked, outlet column, non-uniform conductances); V-cycle symmetric to 1e-14; NaN-poisoned inactive cells untouched; - two Neumann components with opposite imbalances, and a Dirichlet component beside an imbalanced Neumann one (review scenarios): converge, each component right up to its own constant; - speed vs plain SOR at the same stop: 22.7x (128^2), 41x (256^2); - same answers as SOR: PISO MMS 4.6e-8 relative, Taylor–Green divergence 1.4e-9 every step, embedded-circle MMS 7e-8, no-body bit-identity with MG on both solvers, channel+outlet+circle 1.4e-10; CFD1 loads identical to four digits at 0.003 s/step vs 0.094 (30x). CFD1 refinement study (tests/turek_hron_cfd.rs, three grids, 257 s): h = 10 / 6.6 / 5 mm -> control-volume drag 15.6156 / 15.2829 / 15.0988 vs 14.2929 (+9.25 / +6.93 / +5.64%), apparent order 0.71, Richardson extrapolate 14.04; surface route and lift not monotone (flag 2/3/4 cells thick) — the test asserts the measured band at the finest grid. Built with a 4-agent workflow (core, integration, refinement study, adversarial review); the review found no defects and four risks, three fixed here (per-component projection, one symmetric smoother-sweep parameter, acting on `converged` with an SOR fallback) and one recorded (isotropic aggregation loses grid-independence on anisotropic cells). rtx-cfd 301 -> 318 green. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 10:20:25 -07:00
Omar SobhandClaude Fable 5	c25f15b3c4	rtx-cfd + rtx-fea: embedded-boundary PISO and total-Lagrangian SVK — the first two Turek–Hron rungs ... The Turek–Hron geometry decision (omni-cortex docs/turek_hron_geometry_decision.md) chose an embedded boundary on the fixed Cartesian MAC grid over body-fitted unstructured ALE; this commit builds the first rung on each side of the ladder, verified MMS-first. rtx-cfd — solvers::incompressible::{embedded, embedded_body}: EmbeddedPisoSolver is the fixed-grid PISO predictor/projection with per-side domain boundaries (ALE's SideBoundary semantics, so the channel has an outlet), a (x, y, t) boundary-velocity function, and an optional EmbeddedBody (signed distance + surface velocity; circle / rectangle / union). EmbeddedMask classifies cells (fluid iff phi > 0 at the centre) and faces (fluid iff both cells fluid; ghost within 1.5 h; solid deeper); the predictor updates fluid faces only, the projection enforces continuity on fluid cells with zero coefficient across prescribed faces, ghost faces are re-imposed after each projection from a boundary-intercept least-squares linear fit (exact for linear fields), the net ghost mass flux is removed uniformly so a Neumann projection stays compatible, and loads come by two routes: surface-stress reconstruction (full viscous traction) and a control-volume momentum balance. Verified (tests/embedded_mms.rs, tests/turek_hron_cfd.rs): - no body, closed box: bit-identical to PisoSolver over 200 steps; - embedded off-centre circle MMS 16/32/64: velocity orders 0.92, 0.97 (plain PISO 0.85, 0.91), pressure 0.96, 0.90, max |div u| <= 9e-8 on every fluid cell, compatibility correction 6e-4 -> 3e-5; force on the circle vs the exact surface integral: surface route 0.52 -> 0.29 -> 0.15, control-volume route 0.61 -> 0.30 -> 0.15 (both first order, two unrelated readings of the same solution); - Turek–Hron CFD1 (Re 20, h = 10 mm, flag two cells thick), settled to four digits: surface drag 15.71 / lift 0.94, control-volume drag 15.62 / lift 1.08 vs reference 14.29 / 1.119 — the drag routes agree to 0.6%, both +9.5%. A coarse first number; the refinement study waits on a multigrid projection (SOR: 0.1 s/step at 250x41 in the test profile). Fourteenth defect of the campaign: the fixed-grid PISO predictor zeroes the transverse convective face velocity on its domain sides (exact for walls); carried into a solver with an outlet it dropped the OUTGOING momentum flux through the outlet side of the v control volumes, the last column accumulated, and CFD1 went NaN at t ~ 4 s. Found by printing where max |u| lived (x = 2.5) after halving dt changed nothing. Fluxes now come from the stored boundary faces on every side. rtx-fea — elements::total_lagrangian + NonlinearStaticAnalysis:: with_total_lagrangian(): Green–Lagrange strain, second Piola–Kirchhoff stress from a St. Venant–Kirchhoff law on the material's Lamé parameters (plane strain in 2-D), B_L of the current deformation, material plus geometric tangent; dead-load body force per reference volume. Verified (tests/total_lagrangian_svk.rs): - zero displacement: the plane-strain stiffness to 1e-13; - tangent = d f_int/du by central differences at 20% random displacement (Quad4, Quad8, Hex8): relative < 1e-7, symmetric to 1e-12; - a 34-degree rigid rotation produces no internal force; the small-strain routine does (negative control); - manufactured finite-strain solution, body force by FD of the exact P = F S: Quad4 orders 1.95, 1.98; Quad8 2.93, 3.03, 3.02 (an 8% amplitude, Green–Lagrange strain to -0.25 near SVK's compressive limit E = -1/3, broke Newton on fine meshes — the material, not the code; 3% is clean); - Turek–Hron CSM1 at 70x4 Quad8: u(A) = (-7.060, -65.43) mm vs (-7.188, -66.10), 1.0% / 1.8%, converging from below (35x2: -65.14); CSM2: (-0.4604, -16.79) vs (-0.4690, -16.97), 1.1% / 1.8%. rtx-cfd 293 -> 301 green (5 unit + 3 integration), rtx-fea 559 -> 564. Co-Authored-By: Claude Fable 5 <[email protected]>	2026-08-20 08:51:32 -07:00