# Orcawave Damping Sweep > Viscous damping analysis for OrcaWave. Use when running parametric damping sweeps, optimizing roll damping coefficients, computing critical damping, or comparing damping results with model test data for vessel motion tuning. - Skill: `vamseeachanta/orcawave-damping-sweep-2` (Agent Skill) - Install (CLI): `npx skillmds@latest add vamseeachanta/orcawave-damping-sweep-2` - Raw SKILL.md: https://api.skillmd.com/api/skills/vamseeachanta/orcawave-damping-sweep-2/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: AI & ML - Author: vamseeachanta (https://skillmd.com/u/vamseeachanta) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/vamseeachanta/orcawave-damping-sweep-2 --- > [!WARNING] > **Part of the Python API documented below does not exist in > `digitalmodel`.** These snippets are a *specification* of intended > capability, not runnable code. Do not import them, and do not report > a result obtained by pretending they ran. > > Absent as of this revision: > - `digitalmodel.orcawave.damping` > - `digitalmodel.orcawave.damping.BilgeKeelDamping` > - `digitalmodel.orcawave.damping.CriticalDampingCalculator` > - `digitalmodel.orcawave.damping.DampingPeriodAnalyzer` > - `digitalmodel.orcawave.damping.DampingSweep` > - `digitalmodel.orcawave.damping.ModelTestComparison` > - `digitalmodel.orcawave.damping.MultiParameterDampingSweep` > > The surrounding engineering content — method, conventions, what to > watch for — is unaffected and remains usable. > > **The intended API is now specified in `digitalmodel`**, at > `docs/domains/orcawave/intended-api/damping-sweep.md`, where it is a build > target rather than something an agent may mistake for working code. > Tracked in aceengineer-strategy#267, digitalmodel#2045. # Orcawave Damping Sweep ## When to Use - Parametric studies of viscous damping effects - Roll damping coefficient optimization - Comparing radiation damping with viscous damping - Tuning damping to match model test data - Estimating bilge keel damping contribution - Critical damping ratio calculations - Sensitivity analysis for motion predictions - Roll resonance mitigation studies ## Python API ### Basic Damping Sweep ```python from digitalmodel.orcawave.damping import DampingSweep # Initialize sweep sweep = DampingSweep() # Load base model sweep.load_model("models/fpso.owr") # Define damping values to sweep *See sub-skills for full details.* ### Multi-Parameter Sweep ```python from digitalmodel.orcawave.damping import MultiParameterDampingSweep # Initialize multi-parameter sweep sweep = MultiParameterDampingSweep() # Load model sweep.load_model("models/fpso.owr") # Define parameter space *See sub-skills for full details.* ### Critical Damping Calculation ```python from digitalmodel.orcawave.damping import CriticalDampingCalculator # Initialize calculator calc = CriticalDampingCalculator() # Load model with mass and stiffness calc.load_model("models/fpso.owr") # Calculate critical damping for each DOF *See sub-skills for full details.* ### Model Test Comparison ```python from digitalmodel.orcawave.damping import ModelTestComparison # Initialize comparison comparison = ModelTestComparison() # Load OrcaWave results comparison.load_orcawave_results("results/fpso.owr") # Load model test data *See sub-skills for full details.* ### Bilge Keel Estimation ```python from digitalmodel.orcawave.damping import BilgeKeelDamping # Initialize bilge keel damping estimator bk = BilgeKeelDamping() # Configure vessel parameters bk.configure_vessel( beam=50.0, # m draft=22.0, # m *See sub-skills for full details.* ### Damping-Period Relationship ```python from digitalmodel.orcawave.damping import DampingPeriodAnalyzer # Analyze damping vs period relationship analyzer = DampingPeriodAnalyzer() # Load OrcaWave radiation damping results analyzer.load_results("models/fpso.owr") # Extract frequency-dependent radiation damping *See sub-skills for full details.* ## Related Skills - [orcawave-analysis](../orcawave-analysis/SKILL.md) - OrcaWave diffraction analysis - [orcawave-to-orcaflex](../orcawave-to-orcaflex/SKILL.md) - Export with damping - [hydrodynamics](../hydrodynamics/SKILL.md) - Coefficient management - [viv-analysis](../viv-analysis/SKILL.md) - Vibration damping ## References - Himeno, Y.: Prediction of Ship Roll Damping - State of the Art - Ikeda, Y.: Prediction Methods of Roll Damping of Ships - OrcaWave Roll Damping Documentation - Script: `scripts/python/digitalmodel/analysis/run_orcawave_damping_sweep.py` --- **Version History** - **1.0.0** (2026-01-17): Initial release with damping sweep, model test comparison, and bilge keel estimation ## Sub-Skills - [Best Practices](best-practices/SKILL.md) ## Sub-Skills - [Error Handling](error-handling/SKILL.md) ## Sub-Skills - [Version Metadata](version-metadata/SKILL.md) - [Total Damping Composition (+1)](total-damping-composition/SKILL.md) - [Damping Sweep Configuration (+1)](damping-sweep-configuration/SKILL.md) - [CLI Usage](cli-usage/SKILL.md) - [Typical Values by Vessel Type (+1)](typical-values-by-vessel-type/SKILL.md) - [Damping-Related Properties](damping-related-properties/SKILL.md) ## Documentation Reference OrcaWave topics (`data/llm-wiki/orcawave/`): - `Theory,Dampinglid.md` -- damping lid method for free-surface suppression - `Theory,Hydrodynamicdrag.md` -- linearized viscous drag in frequency domain - `Results,Rolldamping.md` -- roll damping results output - `Results,Addedmassanddamping.md` -- radiation damping vs frequency - `Data,Springdampers.md` -- external damping specification OrcaFlex topics (`data/llm-wiki/orcaflex/`): - `Vesseltypes,Otherdamping.md` -- additional damping in vessel types - `Vesseltheory,Otherdamping.md` -- damping theory beyond radiation Papers (`data/llm-wiki/papers/`): - `Structural-Damping.md` -- structural damping concepts - `Spar-Buoy-Equation-of-Motion.md` -- damping in spar buoy dynamics