hydrodynamic-analysis

What it does

Describes comprehensive hydrodynamic analysis for offshore floating structures, including BEM theory, RAOs, added mass and damping, wave loading, and integration with industry tools like WAMIT, AQWA, and OrcaWave.

How it works

Outlines concrete procedures and code snippets for:

• Boundary Element Method concepts: discretizing wetted surfaces, applying Green's functions, solving for potentials, and deriving forces.
• RAOs: defining RAO, solving the frequency-domain equation [-ω²(M + A(ω)) + iωB(ω) + K]·RAO = F_wave to obtain complex RAOs; example calculations for heave RAO provided.
• Added mass and damping: interpolate coefficients across frequency, and estimate infinite-frequency added mass via extrapolation; includes example interpolation and averaging high-frequency data.
• Wave forces: Froude-Krylov force calculation and a diffraction coefficient estimation based on D/λ regimes.
• Hydrostatic stiffness: 6x6 stiffness matrix construction with heave, roll, and pitch terms and coupling terms.
• Wave spectra and irregular seas: JONSWAP spectrum formulation and a calculation of a corresponding response spectrum S_response(ω) = |RAO(ω)|² S_wave(ω) with basic statistics (variance, std, significant amplitude, zero-crossing period).
• Practical applications: a complete RAO analysis workflow taking BEM results and producing RAOs across frequencies and headings.

Commands, file names, and tool names are quoted exactly as shown in the skill where applicable (e.g., WAMIT, AQWA, OrcaWave). The content is presented as explicit mathematical definitions, Python function stubs, and example parameterizations that instruct the agent to perform the steps above.

When to use it

Use when you need:

• RAO calculations for vessel motions (surge, sway, heave, roll, pitch, yaw).
• Frequency-dependent added mass and damping handling and optical extrapolations.
• Prediction of wave loading including Froude-Krylov and diffraction contributions.
• Hydrostatic stiffness and coupling assessments for stability and response.
• Building or validating workflows with WAMIT, AQWA, OrcaWave.
• Both frequency-domain and time-domain considerations (via convolution in time-domain context).

What it can touch

It references and interacts with:

• BEM theory and computations, including panel mesh quality guidelines.
• RAO calculations across 6 DOFs.
• Added mass and damping coefficients (frequency-dependent matrices).
• Wave excitation forces (Froude-Krylov, diffraction).
• Hydrostatic stiffness matrices and coupling terms.
• Wave spectra (JONSWAP) and response spectra calculations.
• Software outputs from WAMIT, AQWA, OrcaWave as inputs to the analysis workflow.

Caveats

The skill provides example parameters, formulas, and code sketches but does not guarantee real-world convergence or validation without actual BEM results. It uses typical constants and heuristic thresholds (e.g., peak-RAO threshold), which may need adaptation for specific vessels and sea states. No licensing or usage restrictions beyond listing MIT and repository metadata in the skill description.