research: Dütsch error budget — settling at one fifth of comparison bands, conservative drift

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/validation/duetsch_re100_kc5_protocol.md

@@ -134,12 +134,19 @@ ledger; verdict PASS or FAIL-CLOSED.
 Scales: `F_ref = 0.5 rho U_max² D`, `U_ref = U_max`; never a near-zero mean
 force as denominator.
 
-- Settling metrics, cycle k−1 → k, phase-aligned by step within the cycle:
-  - waveform `RMS(dFx) / F_ref ≤ .02`;
-  - `|d mean|`, `|d RMS|`, `|d peak|` of Fx, each `/ F_ref ≤ .01`;
-  - scored profiles (fluid-only) `|du| / U_max`, `|dv| / U_max ≤ .03` at the
+- Settling metrics, cycle k−1 → k, phase-aligned by step within the cycle
+  (error budget: one fifth of the tightest comparison band of the same
+  observable, so residual drift cannot obscure a domain or resolution pass):
+  - waveform `RMS(dFx) / F_ref ≤ .002`;
+  - `|d mean|`, `|d RMS|`, `|d peak|` of Fx, each `/ F_ref ≤ .002`;
+  - scored profiles (fluid-only) `|du| / U_max`, `|dv| / U_max ≤ .004` at the
     three phases × four stations;
-  - Morison `|dc_d| ≤ .02`, `|dc_i| ≤ .02`.
+  - Morison `|dc_d| ≤ .004`, `|dc_i| ≤ .004`.
+- Conservative comparison: every domain and cross-resolution criterion is
+  applied to `|difference| + drift_a + drift_b`, where drift is the largest
+  pair metric of that case inside the scored window.
+- These constants (protocol.py SETTLE, DOMAIN, CROSS) are frozen before any
+  physical result; no post-result loosening.
 - Rule: all metrics for N = 3 consecutive whole paper cycles → settled.
 
 Cycle indexing (worked example, binding). Paper cycle k spans

research/duetsch_re100_kc5/analyze.py

@@ -117,7 +117,9 @@ def main(argv):
         entry.update(duration_T=case["steps"] / case["T"], K_case=k_case, pairs=pairs,
                      coverage={k: coverage(case, k) for k in sorted(cycle_slices(case)) if k > p.DISCARD},
                      no_donor=float(case["diag"][:, 13].sum()), eq_only=float(case["diag"][:, 12].sum()))
-        if window:
+        if window:  # residual drift inside the scored window (pairs K..K+2)
+            entry["window_drift"] = {key: max(pairs[k][key] for k in window)
+                                     for key in ("wave", "profile", "morison")}
             entry["morison_obs"] = cycle_morison(case, window)
             entry["morison"] = {name: cycle_morison(case, window, fx)
                                 for name, fx in candidates(case).items()}
@@ -146,6 +148,19 @@ def main(argv):
                 d = max(max(abs(prof[key][0] - fine_p[key][0]), abs(prof[key][1] - fine_p[key][1]))
                         for key in keys) / case["u_max"]
                 entry.setdefault("profile_max_vs_finest", {})[k] = float(d)
+        ref_entry = report["cases"][cases.index(fine)]
+        for entry in report["cases"]:  # conservative: difference + both drifts
+            if entry is ref_entry:
+                continue
+            drift = {key: entry["window_drift"][key] + ref_entry["window_drift"][key]
+                     for key in ("wave", "profile", "morison")}
+            dm = max(abs(entry["morison"]["cme"][0] - ref_entry["morison"]["cme"][0]),
+                     abs(entry["morison"]["cme"][1] - ref_entry["morison"]["cme"][1]))
+            entry["conservative"] = dict(
+                wave=entry["wave_rms_vs_finest"] + drift["wave"],
+                profile=max(entry.get("profile_max_vs_finest", {}).values(), default=math.inf)
+                + drift["profile"],
+                morison_cme=dm + drift["morison"])
     print(json.dumps(report, indent=1, default=float))
 
 

research/duetsch_re100_kc5/protocol.py

@@ -16,8 +16,12 @@ STATIONS = (-0.6, 0.0, 0.6, 1.2)          # lab-fixed x/D from the mean position
 PHASES = (180.0, 210.0, 330.0)            # degrees; bins [p, p + 1)
 X2 = tuple(np.round(np.arange(-1.5, 1.5001, 0.05), 10))  # declared x2/D points
 DISCARD, LAST_SCORED, N_PAIRS = 2, 11, 3   # cycles 0..2 discarded, cap 12 T
-SETTLE = dict(wave=.02, scalar=.01, profile=.03, morison=.02)
-DOMAIN = dict(wave=.01, morison=.02, profile=.02)  # a-priori, vs the 60 D reference
+# A-priori bands. Settling is one fifth of the tightest comparison band of the
+# same observable, and comparisons add both cases' residual window drift
+# (conservative: |difference| + drift_a + drift_b <= band).
+DOMAIN = dict(wave=.01, morison=.02, profile=.02)  # vs the 60 D reference at D = 40
+CROSS = dict(wave=.02, profile=.02)                # D40 vs D80
+SETTLE = dict(wave=.002, scalar=.002, profile=.004, morison=.004)
 
 
 def amplitude(D):