capytaine.post_pro.impedance module

Computation of the impendance matrix.

capytaine.post_pro.impedance.impedance(dataset, dissipation=None, stiffness=None)[source]

Complex-valued mechanical impedance matrix. See Falnes for more theoretical details:

@book{falnes2002ocean,
      title={Ocean Waves and Oscillating Systems: Linear Interactions Including Wave-Energy Extraction},
      author={Falnes, J.},
      isbn={9781139431934},
      url={https://books.google.com/books?id=bl1FyQjCklgC},
      year={2002},
      publisher={Cambridge University Press}
}
Parameters:

  • dataset (xarray Dataset) – The hydrodynamical dataset. This function supposes that variables named ‘inertia_matrix’ and ‘hydrostatic_stiffness’ are in the dataset. Other variables can be computed by Capytaine, by those two should be manually added to the dataset.

  • dissipation (array, optional) – An optional dissipation matrix (e.g. Power Take Off) to be included in the impedance. Default: none.

  • stiffness (array, optional) – An optional stiffness matrix (e.g. mooring stiffness) to be included in the impedance. Default: none.

Returns:

The impedance as an array depending of omega and the degrees of freedom.

Return type:

xarray DataArray

capytaine.post_pro.impedance.rao_transfer_function(dataset, dissipation=None, stiffness=None)[source]

Complex-valued matrix used for the computation of the RAO.

Parameters:

  • dataset (xarray Dataset) – The hydrodynamical dataset. This function supposes that variables named ‘inertia_matrix’ and ‘hydrostatic_stiffness’ are in the dataset. Other variables can be computed by Capytaine, by those two should be manually added to the dataset.

  • dissipation (array, optional) – An optional dissipation matrix (e.g. Power Take Off) to be included in the transfer function. Default: none.

  • stiffness (array, optional) – An optional stiffness matrix (e.g. mooring stiffness) to be included in the transfer function. Default: none.

Returns:

The matrix as an array depending of omega and the degrees of freedom.

Return type:

xarray DataArray