Hydrostatic and Hydrodynamic Analysis Suite

This repository contains numerical tools and engineering workflows developed for hydrodynamic analysis, stability assessment, and ocean wave data processing.

The repository is organized into three main projects:

1. LTTD_sump – Analytical/semi-analytical frequency-domain hydrodynamic model of the NIOT LTTD sump floating caisson (linear potential flow; no CFD/BEM/WAMIT). Formerly named "Androth."
2. Buoy – WAMIT-based hydrodynamic analysis of a NIOT oceanographic buoy designed for monitoring wind conditions in the Indian Ocean.
3. Spectrum – Processing of ERA5 wave reanalysis datasets for environmental characterization.

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Repository Structure

KAKWA/
├── LTTD_sump/
│   ├── data/                     SI-unit JSON inputs
│   ├── hydro/                    restoring, added mass, damping, inertia
│   ├── dynamics/                 transfer function, RAO, response spectrum
│   ├── spectra/                  JONSWAP (pm.py reserved)
│   ├── plots/                    figure rendering
│   ├── tests/                    pytest unit tests
│   ├── results/                  generated summary.json + figures/ (git-ignored)
│   ├── main.py
│   ├── heave_model.py
│   ├── README.md
│   ├── PROJECT_SPEC.md
│   └── PROJECT_DOCUMENTATION.md
│
├── Buoy/
│   ├── scripts/                  geometry, stability, WAMIT input generators
│   ├── fill_levels/              fill_<tag>/Inputs + fill_<tag>/Outputs per case
│   ├── reference files/          reference WAMIT cases (androth.*) + context
│   ├── Output/                   plotting scripts (rao.py, rao_colab.py)
│   ├── README.md
│   └── PROJECT_DOCUMENTATION.md
│
├── Spectrum/
│   ├── spectrum.py
│   └── README.md
│
├── README.md
└── .gitignore

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Projects

LTTD_sump

Analytical/semi-analytical frequency-domain hydrodynamic model of the NIOT LTTD sump floating caisson, built on linear potential-flow theory only (no CFD, OpenFOAM, BEM, or WAMIT). It computes hydrostatic restoring, added mass, damping, transfer functions, RAOs for heave and roll, the JONSWAP wave spectrum, and motion response statistics. WAMIT/Capytaine/AQWA comparison is a later validation phase. Formerly named "Androth."

See LTTD_sump/README.md for details, and LTTD_sump/PROJECT_DOCUMENTATION.md for the full technical record.

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Buoy

Hydrodynamic analysis of a cylindrical ocean buoy containing internal fuel-cell tanks. Multiple fill levels are evaluated to study the influence of internal free-surface effects on stability and motion response. WAMIT is used to generate added mass, damping, excitation forces, and RAOs.

See Buoy/README.md for details.

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Spectrum

Utility for processing ERA5 wave datasets stored in NetCDF format. Selected wave parameters are extracted, cleaned, and exported into tabular formats for use in hydrodynamic analyses.

See Spectrum/README.md for details.

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Requirements

pip install numpy scipy matplotlib pandas xarray openpyxl netcdf4 pytest

Note: numpy/scipy/matplotlib are used by LTTD_sump (and pytest for its tests); xarray/pandas/openpyxl/netcdf4 are used by Spectrum. Buoy generates WAMIT input files with numpy and runs the solver externally in WAMIT. Ensure matplotlib is built against the installed NumPy major version.

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Getting Started

LTTD_sump

cd LTTD_sump
python main.py

Buoy

Follow the workflow described in:

Buoy/README.md

Spectrum

cd Spectrum
python spectrum.py

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Notes

Large datasets, generated outputs, and temporary files are excluded from version control through .gitignore to keep the repository lightweight and focused on source code and documentation.