netsse.analys.spec.spec1d_to_params

netsse.analys.spec.spec1d_to_params(S, freq, unit_freq='rad/s', smooth_Tp=False)

Computes the main sea state parameters from a given 1-D wave spectrum.

Parameters:

• S (array_like) – 1-D wave spectrum. If S has more than one dimension, then one axis must have a length Nfreq.

• freq (array_like of shape (Nfreq,)) – Set of discretized frequencies.

• unit_freq ({'rad/s','Hz'}, optional) –

  Unit of the frequencies:

  • ’rad/s’ :

    The variable freq denotes the circular frequencies in radians per second.

  • ’Hz’ :

    The 1-D wave spectrum is expressed as a function of frequency in Hertz.

• smooth_Tp (bool, default False) – Specify whether the output Tp value should be smoothened by fitting a polynomial of order 3 in the vicinity of the spectral peak and estimating the peak period through the fitted polynomial.

Returns:

• m (array_like of shape (6,…,)) – Spectral moments \([m_{-1},m_0,m_1,m_2,m_3,m_4]\).

• Hm0 (float, or array_like) – Spectral significant wave height [m].

• Tp (float, or array_like) – Peak wave period [s].

• Tm01 (float, or array_like) – Mean wave period [s].

• Tm02 (float, or array_like) – Zero up-crossing period [s].

• Tm24 (float, or array_like) – Mean crest period [s].

• TE (float, or array_like) – Mean energy period [s].

• Sm02 (float, or array_like) – Significant wave steepness [-].

• epsilon (float, or array_like) – Spectral bandwidth [-].

• Qp (float, or array_like) – Goda’s peakedness parameter [-].

See also

spec2d_to_params

Computes a set of overall parameters characterizing the sea state from the 2-D wave spectrum.

Example

>>> m, Hm0, Tp, Tm01, Tm02, Tm24, TE, Sm02, epsilon, Qp =
...     spec1d_to_params(S,freq,unit_freq='rad/s',smooth_Tp=False)