| --- |
| license: cc-by-4.0 |
| pretty_name: digitalmodel Diffraction RAOs (multi-vessel, de-identified) |
| tags: |
| - analysis-results |
| configs: |
| - config_name: hydrostatics |
| data_files: hydrostatics.parquet |
| - config_name: rao |
| data_files: rao.parquet |
| --- |
| |
| # digitalmodel Diffraction RAOs (multi-vessel, de-identified) |
|
|
| Analysis/computation results published for query + visualization via the Hugging Face |
| datasets-server API. One row per (vessel, solver, damping, dof, frequency, heading). |
| Vessels are referenced only by de-identified vessel_db IDs. |
| |
| ## Tables |
| |
| | config | rows | cols | |
| |---|---|---| |
| | `hydrostatics` | 5 | 7 | |
| | `rao` | 8448 | 11 | |
| |
| ## Schema 1.1.0 — `solver` column |
| |
| The `rao` table now carries a `solver` column (`AQWA` \| `OrcaWave`), added when the first |
| vessel gained results from two solvers. Filter on `vessel_id` **and** `solver` (and |
| `damping_zeta_pct`); rows published under schema 1.0.0 were backfilled from the vessel |
| table below at the 1.1.0 migration and are otherwise byte-identical. |
|
|
| ## Series in `rao` |
|
|
| | vessel_id | solver | damping_zeta_pct | rows | basis | |
| |---|---|---|---|---| |
| | `install_bokalift_2` | OrcaWave | 5, 10 | 600 | parametric hull from public particulars | |
| | `drill_samsung96k_1` | AQWA | 0 | 2700 | hull-class-level de-identified model, survival loading condition | |
| | `drill_samsung96k_1` | OrcaWave | 0 | 2574 | same hull class/condition; radiation-only (no external damping), open moonpool (no lid) | |
| | `drill_samsung96k_1` | OrcaWave | 5 | 2574 | as ζ=0 plus external linear roll damping B44 (total roll ζ ≈ 5 %) | |
| |
| ## Data-quality notes |
| |
| **Screening-grade — faithful-to-solver ≠ correct for design.** No model here is class-approved. |
| |
| ### install_bokalift_2 (OrcaWave, parametric screening) |
| |
| - **Low-frequency artifact (flagged, not omitted):** in `rao`, heave & sway at freq ≤ 0.35 rad/s (T ≥ 18 s) in non-beam headings are physically implausible (heave ≈ 7–9 m/m where beam seas correctly show ≈ 1.1). 40 rows carry `reliability = "low_freq_artifact"`. Use freq ≥ 0.5 rad/s. Tracked: digitalmodel#1548. |
| - **Withheld table — `added_mass_damping`:** the source matrices declare units kg / kg·m² but magnitudes are consistent with te / te·m² (~1000× off, e.g. heave added-mass 58,447 vs ~1e8 kg expected). Withheld pending unit reconciliation. Tracked: digitalmodel#1550. |
| - **Withheld — operation-envelope (Hs/Tp) limits:** derived limits reach implausible values (~17 m Hs heavy-lift) and would mislead as operational limits. A class panel mesh is required first. |
| - **Roll at resonance is high** (23.5 deg/m at ζ=5 %, 19.2 at ζ=10 %) — a real, expected consequence of light damping, not an artifact. |
| |
| ### drill_samsung96k_1 · AQWA (ζ = 0) |
| |
| - **`damping_zeta_pct = 0` means NO external/viscous roll damping** — radiation damping only. |
| The roll peak (15.6 deg/m at T = 19 s, beam seas) is therefore an undamped potential-flow |
| upper bound, not an operability prediction; apply an external roll damping model before use. |
| - **Resonance band flagged (50 rows `reliability = "undamped_resonance"`):** roll rows at |
| T = 18.48 and 18.98 s (all headings) are damping-controlled, matching the flag treatment of |
| the OrcaWave ζ=0 series. Coupled sway/yaw are NOT flagged here — the AQWA grid straddles the |
| resonance, so their contamination is negligible (sway ≤ 1.14 m/m, yaw ≤ 0.064 deg/m). |
| - **Frequency band is roll-focused:** 18 frequencies covering T ≈ 15.5–31.4 s (refined around |
| the roll-response band). No rows outside this band — absence is by scope, not omission. |
| - **Moonpool:** the panel model includes moonpool walls with no damping lid; moonpool-resonance |
| effects near the moonpool natural period are expected and not suppressed. |
| - Long-period sanity passed: beam-seas heave → 1.0 m/m and head-seas surge → 0.95 m/m at T = 31.4 s. |
| - Headings span −180°…180° at 15° (25 values). |
| |
| ### drill_samsung96k_1 · OrcaWave (ζ = 0 and ζ = 5) |
| |
| - **Grid:** 33 frequencies (T ≈ 4–31.4 s, refined 10–22 s at 0.5 s) × 13 headings (0°–180° at |
| 15°; port/starboard symmetry assumed) × 6 DOFs = 2,574 rows per series. Phases in the |
| **Orcina lag** convention — align conventions before phase-level comparison with AQWA. |
| - **ζ = 0 series — resonance band flagged (117 rows `reliability = "undamped_resonance"`):** |
| radiation-only roll damping for this hull is ζ ≈ 0.2 % critical, so the roll RAO at |
| resonance (358 deg/m at T = 18.5 s, beam seas) and the coupled sway/yaw peaks are |
| **damping-controlled numerical upper bounds, not physical response predictions**. Roll, |
| sway and yaw rows with T = 17.9–19.1 s carry the flag. Off-resonance rows are usable |
| screening values. The open moonpool (no damping lid) is also unsuppressed in this run. |
| - **ζ = 5 series:** adds external linear roll damping B44 equivalent to ≈ 5 % total critical; |
| beam-seas roll peak drops to 4.48 deg/m at T = 18.5 s (~80× below the ζ=0 value) — use this |
| series as the damping-sensitivity anchor; match your own damping budget before design use. |
| - **Cross-solver agreement (same hull, both ζ=0):** off-resonance beam-seas roll RAOs agree |
| with the AQWA series within ~12–18 % — consistent for undamped potential-flow codes on |
| different grids. Resonance-peak *magnitudes* are NOT comparable between the two ζ=0 series: |
| the AQWA grid straddles the peak while the OrcaWave grid samples it exactly (grid sampling, |
| not physics). Roll natural period agrees at 18.5–19.0 s in both codes. |
| - **Withheld — added mass & damping matrices:** present in the source results but not yet |
| published pending the same unit reconciliation as digitalmodel#1550. |
| |
| ## Provenance |
| |
| - Source repo: `digitalmodel` · solvers: `orcawave-diffraction@1537` (install_bokalift_2), |
| AQWA v261 licensed-run lane (drill_samsung96k_1 AQWA, run `lr_acma_bb24945c4b8b`), |
| OrcaWave 11.x licensed-run lane (drill_samsung96k_1 OrcaWave: ζ=0 run `lr_acma_2a4a51f24387`, |
| ζ=5 run `lr_acma_36fb1ffbc5e0`) |
| - Schema version: `1.1.0` (adds `solver`; 1.0.0 rows backfilled per the series table) |
| - Source snapshots (sha256): |
| |
| - `hydrostatics.parquet` — sha256 `cb0141548b6bf07f3892560f4a564147bb76648fcc7ea1c3383577ff62357f53` |
| (adds 3 drill_samsung96k_1 rows: class-level analysis mass for the OrcaWave series; the AQWA |
| row's `mass_te` is null — genuinely absent from its de-identified source. CoG/CoB/stiffness |
| remain withheld: GM-recoverable.) |
| - `rao.parquet` — sha256 `d855c015efb7bd13e05429da2e54613cab213421fde4f4eb57c967b53f5a5347` |
| (2026-07-16b: AQWA resonance-band flags added; values byte-identical to the prior revision) |
| - drill_samsung96k_1 AQWA de-identified source JSON — sha256 `ef6e7d90b52b4bf730c94e7aebcc1b295008ccb9b9c80ad3e0ef1a5d26c05dec` |
| - drill_samsung96k_1 OrcaWave ζ=0 de-identified source JSON — sha256 `af4b37cb0acde7d7f68b7c2f60ac2cc34b8928caeb5e7aa3e06ade13ad81a081` |
| - drill_samsung96k_1 OrcaWave ζ=5 de-identified source JSON — sha256 `36acd2d4943a97a44d2b31fa7bebda7623ef56b6bc0d9bb304af6b3f05bf5fa5` |
|
|
| Vessels are de-identified: `install_bokalift_2` from public particulars; `drill_samsung96k_1` |
| identified only at hull-class level. Not a run-identity ledger (that is the separate |
| `aceengineer/*-runs` contract). |
|
|
| Nulls are genuine missing values (non-finite floats were coerced to null). Load a table: |
| `pandas.read_parquet(hf_hub_download("aceengineer/digitalmodel-diffraction-rao", "<config>.parquet", repo_type="dataset"))`. |
|
|
| Live visualizations of this dataset: https://www.aceengineer.com/reports/diffraction/ |
|
|
