From 78637faffca13da3f4356ae14a78a50e4faddad0 Mon Sep 17 00:00:00 2001 From: Claude Date: Fri, 30 Oct 2026 14:59:52 +0000 Subject: [PATCH] =?UTF-8?q?docs:=20VIV=20predeclare=20=E2=80=94=20(30D,30D?= =?UTF-8?q?)=20centre,=20conditional=20.01D=20seed,=20150-cycle=20budget?= =?UTF-8?q?=20incl.=20scoring?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-Authored-By: Claude Opus 5.5 --- docs/validation/leontini_viv_predeclare.md | 39 +++++++++++++--------- 1 file changed, 24 insertions(+), 15 deletions(-) diff --git a/docs/validation/leontini_viv_predeclare.md b/docs/validation/leontini_viv_predeclare.md index 1160b31..91725f8 100644 --- a/docs/validation/leontini_viv_predeclare.md +++ b/docs/validation/leontini_viv_predeclare.md @@ -27,8 +27,10 @@ this page is jointly agreed. - D = 40, MRT, dense double buffer; U_lat = .04, nu = U D / 150 = .010667, tau = .532. -- Box 75 D × 60 D (3000 × 2400) with the cylinder 30 D from the inlet, 45 D - from the outlet, centred in y (Kolahdouz §4.1.1). +- Box [0, 75 D] × [0, 60 D] (3000 × 2400) with the cylinder centre at + (30 D, 30 D): 30 D from the inlet, 45 D from the outlet, centred in y + (Kolahdouz §4.1.1). Qin's own box ([0, 40 D] × [0, 20 D], centre (10 D, 10 D)) + is the target paper's, not ours. - Boundaries: uniform Zou–He inlet, NEQ outlet (rho = 1, backflow clamp), free-slip y walls. Kolahdouz uses a traction outlet: declared mismatch. - Qin's own VIV box (40 D × 20 D) is not used; a smaller box would be a @@ -55,22 +57,29 @@ this page is jointly agreed. ## Window, failure semantics, acceptance (engineering, development stage) -- Start: fluid at rest at U = 0 except the uniform inlet (impulsive start as - in the reference), body at rest. The reference states no perturbation; a - numerically symmetric start can delay or suppress lift, so one declared - seed is used: initial structural displacement y0 = +.05 D (2 cells) with - v0 = 0, released at t = 0. No other perturbation; not changed afterwards. +- Start (source-faithful): fluid at rest except the uniform inlet, body at + rest at the declared centre, y(0) = v(0) = 0. +- Seed policy (conditional, declared): exact mirror symmetry can suppress + lift. If max |y| over the last 5 T_n before t = 40 T_n (200,000 steps) is + below .01 D, apply one labelled seed at that step: body centre displaced by + +.01 D in y (v = 0), `seed_applied=true` and its step logged; the run + continues under the same cap. Missing shedding is a diagnostic, never an + "A = 0 pass"; the seed is not changed or repeated after seeing results. - Response cycles: delimited by consecutive upward zero crossings of y about its running mean; per-cycle peak = max |y − mean| in that cycle. - Settled when the per-cycle peak changes ≤ 2 % between consecutive 10-cycle - windows and the last 5 cycle peaks agree within 1 %. The 20 scoring cycles - follow settling and are included in the cap of 150 response cycles from - t = 0 (about 150 × 5,000 = 750,000 steps, t U/D ≈ 750); total steps and - t U/D are reported. -- Growth transient vs instability: amplitude growth from the seed that stays - below 1.0 D (about twice the largest reference peak, .551 D) is a physical - transient and is not a failure by itself. Instability = |y| > 1.0 D, a - non-finite value, or the offset box being reached. + windows and the last 5 cycle peaks agree within 1 %. Budget: 150 response + cycles from the start of motion, including the 20 scoring cycles, so + settling must complete by response cycle 130; the score uses the first 20 + cycles after settling. Cap miss → FAIL-CLOSED. +- Durations reported: total steps, t U/D, N_resp, measured T_resp (mean + upward-crossing interval); N_resp / f_n only as a labelled secondary clock, + never as the settling unit. +- Growth transient vs instability: an envelope that rises and then saturates + under the settling windows is a physical transient. Instability = + |y| > 1.0 D (about twice the largest reference peak, .551 D), a non-finite + value, the offset box being reached, or an envelope still growing at the + cap. - FAIL-CLOSED and reported (no sub-iteration, no RHS or parameter retune): unsettled at the cap, instability as defined above (possible weak-coupling instability at m* ≈ 2.55), or no_donor > 0.