| name | orcawave-analysis-orcfxapi-result-extraction |
| description | Sub-skill of orcawave-analysis: OrcFxAPI Result Extraction (+3). |
| version | 1.0.0 |
| category | engineering |
| type | reference |
| scripts_exempt | true |
OrcFxAPI Result Extraction (+3)
OrcFxAPI Result Extraction
| Property | Gotcha | Fix |
|---|
.frequencies | Returns Hz, not rad/s | Multiply by 2 * np.pi |
.frequencies | Returns descending order | np.argsort() ascending before comparison |
.displacementRAOs | Shape (nheading, nfreq, 6) | Transpose to (nfreq, nheading, 6) |
| Rotational RAOs (indices 3,4,5) | In rad/m | np.degrees() for deg/m (AQWA convention) |
.addedMass, .damping | Follow frequency order | Apply same sort index as frequencies |
Unit Conversion: WAMIT .frc → spec.yml
| Source | Mass Unit | Inertia Unit | Density | To spec.yml |
|---|
WAMIT .frc (RHO=1) | te | te·m² | 1 te/m³ | ×1000 for kg, kg·m² |
OrcaWave .owd | te | te·m² | 1 te/m³ | ×1000 for kg, kg·m² |
| spec.yml | kg | kg·m² | kg/m³ | — (canonical) |
TRAP: When porting from WAMIT .frc to spec.yml, multiply inertia by 1000 (te·m² → kg·m²). Do NOT multiply twice — the ISSC TLP case 2.5 had inertia tensors 1000× too large (8.02e13 vs correct 8.02e10) from double conversion.
Phase Correlation for Zero-Magnitude DOFs
Fixed DOFs (e.g. heave/roll/pitch on TLPs) produce zero RAO magnitudes. Phase is undefined (atan2(0,0) noise), so:
multi_solver_comparator.py: when peak_mag < 1e-10, overrides phase correlation to r = 1.0validate_owd_vs_spec.py: skips DOFs with max_diff < 1e-6 in pass/fail verdict
QTF Settings Guard
When qtf_calculation: false in spec.yml, do NOT include any QTF-related keys in the OrcaWave YAML:
QTFMinCrossingAngle, QTFMaxCrossingAngle, PreferredQuadraticLoadCalculationMethod- These cause "Change not allowed" errors from OrcaWave
QuadraticLoadPressureIntegration: No is safe (explicitly disabling)
