rtx-cfd: overset A-P3 — the falsifier plate on the overset (FAILS the registered gates by one order less than the staircase); wall force; composite pressure-level pin; Schwarz stall detection

patch_gen::{stadium, graded_fractions}: the falsifier plate as a stadium O-grid (semicircular ends r = half-thickness; 16 cells per end arc, straights graded 0.30 h -> h at 1.15, offset 6 h, 12 rows stretched 4x; 148x12 cells, every ray a normal, worst non-orthogonality 4 deg). CurvilinearPisoSolver::surface_force (+ PatchLoad): F = sum(-p_f S_f + mu (grad u + grad u^T)_f . S_f) on the wall faces with the wall cell's LSQ gradients (wall Dirichlet in the velocity fit); HELD on the phantom circle against the exact stress integral: 1.3e-2 / 6.3e-3 / 3.6e-3 at n = 32/64/128 (orders 1.05 / 0.81), 22x the staircase's accuracy. OversetPisoSolver: the composite p' level pinned to zero mean over the active cells every round (the coupled problem is pure Neumann; the temporal warm start handed each step's level to the next — background pressure 1e7 growing 5e4 per step on the falsifier; an unpinned level also inflated the relative Schwarz stop); stall detection (no progress over three rounds = the inner solvers' noise floor; 6560 of 150k steps burned the 20-round cap at n = 64, a 7.5 h n = 128 march); schwarz_stalled in the result. tests/overset_falsifier.rs (records; RTX_OVERSET_FALSIFIER_STRICT asserts the registered gates, _LADDER runs dt/2 and dt/4, _TRACE the top-12 spike steps): max spike 594 / 981 / 1720 N/m at dt / dt/2 / dt/4 (staircase 6490 / 12600 / 25600), rms spike 61-89 (810), far probe 502-1509 (7900), KE injection 0.16-0.21 J/m per event on the common cell set (2.6) — every large spike a ~104-cell full-row reclassification; exponent -0.77 (-1.0). The registered 5% gate (8.75 N/m) is missed 68x: the overset's own reclassification impulse is the finding (omni-cortex overset_metal_campaign.md §5.10); P3b = locate per cell, then the fringe flux balance. tests/patch_stadium.rs, curvilinear_loads.rs, overset_common::plate_patch. Co-Authored-By: Claude Fable 5.1 <[email protected]> Claude-Session: https://claude.ai/code/session_01X2GmJXeQ2njUecEKiJZ1G2
2026-09-05 04:32:43 -07:00
parent afd1bff6ee
commit e2edff9b1d
8 changed files with 943 additions and 2 deletions
@@ -148,3 +148,98 @@ pub fn channel_varying_skew(
    }
    PatchMesh::from_nodes(nx, ny, x, y, periodic_x.then_some([lx, 0.0]))
 }
+
+/// Spacings along a straight of `length` that grow geometrically from `d0`
+/// at both ends (ratio `ratio`) to at most `d1` in the middle, symmetric;
+/// returns the cumulative fractions `0 ..= 1`. The count adapts to the
+/// length.
+pub fn graded_fractions(length: f64, d0: f64, d1: f64, ratio: f64) -> Vec<f64> {
+    // One end's graded run, until the spacing reaches d1 or half the length.
+    let mut run = Vec::new();
+    let mut d = d0;
+    let mut acc = 0.0;
+    while d < d1 && acc + d < 0.5 * length {
+        run.push(d);
+        acc += d;
+        d *= ratio;
+    }
+    let middle = length - 2.0 * acc;
+    let n_mid = ((middle / d1).round() as usize).max(1);
+    let d_mid = middle / n_mid as f64;
+    let mut spacings = run.clone();
+    spacings.extend(std::iter::repeat_n(d_mid, n_mid));
+    spacings.extend(run.iter().rev());
+    let total: f64 = spacings.iter().sum();
+    let mut fr = Vec::with_capacity(spacings.len() + 1);
+    let mut s = 0.0;
+    fr.push(0.0);
+    for w in &spacings {
+        s += w;
+        fr.push(s / total);
+    }
+    let last = fr.len() - 1;
+    fr[last] = 1.0;
+    fr
+}
+
+/// An O-grid around a STADIUM (a rectangle of half-length `hx` and
+/// half-thickness `r` with semicircular ends of radius `r`, the plate of
+/// the fresh-cell falsifier rounded at its ends) centred at `centre`: the
+/// inner ring is the stadium, the outer ring its normal offset by
+/// `offset`, so every ray is a normal (orthogonal cells). Along the body
+/// the straights are graded from the arc spacing `d0 = π r / k_arc` at the
+/// tangent points to `d_straight` in the middle (ratio `grade`); each end
+/// arc carries `k_arc` cells. Across, `nn` cells with the geometric
+/// `stretch` (wall spacing = `offset · (g − 1)/(g^nn − 1)`). `s` runs
+/// CLOCKWISE (the right-handed frame `PatchMesh` needs), starting at the
+/// top-left tangent point. Periodic.
+#[allow(clippy::too_many_arguments)]
+pub fn stadium(
+    centre: [f64; 2],
+    hx: f64,
+    r: f64,
+    offset: f64,
+    k_arc: usize,
+    d_straight: f64,
+    grade: f64,
+    nn: usize,
+    stretch: f64,
+) -> CfdResult<PatchMesh> {
+    let a = hx - r; // half-length of the straights
+    let d0 = PI * r / k_arc as f64;
+    let straight = graded_fractions(2.0 * a, d0, d_straight, grade);
+    let mut inner = Vec::new();
+    let mut outer = Vec::new();
+    let mut push = |p: [f64; 2], n: [f64; 2]| {
+        inner.push([centre[0] + p[0], centre[1] + p[1]]);
+        outer.push([
+            centre[0] + p[0] + offset * n[0],
+            centre[1] + p[1] + offset * n[1],
+        ]);
+    };
+    // Top straight, left → right (clockwise around the body).
+    for &f in &straight[..straight.len() - 1] {
+        push([-a + f * 2.0 * a, r], [0.0, 1.0]);
+    }
+    // Right arc, from +90° down to −90° (exclusive of both ends' duplicates
+    // handled by the straights: include angles strictly between).
+    for k in 0..k_arc {
+        let th = PI / 2.0 - PI * k as f64 / k_arc as f64;
+        let (s, c) = th.sin_cos();
+        push([a + r * c, r * s], [c, s]);
+    }
+    // Bottom straight, right → left.
+    for &f in &straight[..straight.len() - 1] {
+        push([a - f * 2.0 * a, -r], [0.0, -1.0]);
+    }
+    // Left arc, from −90° down to −270°.
+    for k in 0..k_arc {
+        let th = -PI / 2.0 - PI * k as f64 / k_arc as f64;
+        let (s, c) = th.sin_cos();
+        push([-a + r * c, r * s], [c, s]);
+    }
+    // Close the ring: the last point repeats the first.
+    inner.push(inner[0]);
+    outer.push(outer[0]);
+    transfinite(&inner, &outer, nn, stretch, Some([0.0, 0.0]))
+}