From 778d3185e5aaab1ae161265a159b601250104698 Mon Sep 17 00:00:00 2001 From: Claude Date: Fri, 30 Oct 2026 14:57:50 +0000 Subject: [PATCH] =?UTF-8?q?docs:=20VIV=20predeclare=20=E2=80=94=20source-v?= =?UTF-8?q?erified=20box/position,=20seed,=20response-cycle=20window,=20in?= =?UTF-8?q?stability=20definition?= 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, 29 insertions(+), 10 deletions(-) diff --git a/docs/validation/leontini_viv_predeclare.md b/docs/validation/leontini_viv_predeclare.md index f2999d8..1160b31 100644 --- a/docs/validation/leontini_viv_predeclare.md +++ b/docs/validation/leontini_viv_predeclare.md @@ -8,9 +8,15 @@ this page is jointly agreed. ## Primary case (one case) -- Reference: Kolahdouz et al., arXiv:2003.12046, §4.1.1 (setup) and Qin et - al., arXiv:2003.12186, §4.5 (maximum amplitudes at U_red = 3…8: .075, .551, - .520, .459, .370, .084 D, as quoted by Grok/Astra from the text). +- Reference: Qin et al., arXiv:2003.12186, §4.5 (maximum amplitudes at + U_red = 3…8: .075, .551, .520, .459, .370, .084 D in the text, as quoted by + Grok/Astra) for the target; setup from Kolahdouz et al., arXiv:2003.12046, + §4.1.1 (read 2026-10-30 via ar5iv): U* sweep 3–8 with amplitudes only in + Fig. 3(b) (no text values), domain [−30, 45] D × [−30, 30] D with the + cylinder "initially at rest and centered at the origin", uniform inflow on + the left, zero normal traction and tangential velocity at the outlet, zero + normal velocity and tangential traction on y = ±30 D; no initial + perturbation and no total simulated time stated. - Re = 150, U* = U/(f_n D) = 5, m/(rho D²) = 2 (m* = rho_s/rho_f = 8/pi), zeta = 0, f_n = sqrt(K/M)/(2 pi) in vacuum. Transverse DOF only. - Target: A_max = .520 D (peak amplitude, Qin §4.5). Multi-code reference @@ -21,8 +27,8 @@ 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, Kolahdouz class); cylinder position as in - Kolahdouz (OPEN: confirm; default 20 D from the inlet, centred in y). +- 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). - 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 @@ -49,12 +55,25 @@ this page is jointly agreed. ## Window, failure semantics, acceptance (engineering, development stage) -- Settled when the per-cycle peak |y| changes ≤ 2 % between consecutive - 10-cycle windows and the last 5 cycle peaks agree within 1 %; cap 150 - oscillation cycles. +- 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. +- 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. - FAIL-CLOSED and reported (no sub-iteration, no RHS or parameter retune): - unsettled at the cap, |y| beyond the declared offset box, no_donor > 0, or a - growing/diverging amplitude (coupling instability at m* ≈ 2.55). + unsettled at the cap, instability as defined above (possible weak-coupling + instability at m* ≈ 2.55), or no_donor > 0. - Score over the 20 cycles after settling: A_max/D (mean of cycle peaks) and f/f_n (reported; no target). - Acceptance: |A_max − .520 D| ≤ .052 D (±10 %), stated together with the