Torsethaugen#

class waveresponse.Torsethaugen(freq, freq_hz=False)[source]#

Torsethaugen spectrum, given as:

S(w) = alpha * S_1(w; Hs_1, Tp_1) * gamma ** b + S_2(w; Hs_2, Tp_2)

where,

S_i(w) = A_i / w ** 4 * exp(-B_i / w ** 4)

and,

b = exp(-(w - wp_1) ** 2 / (2 * sigma ** 2 * wp_1 ** 2))

Furthermore,

A_i = 3.26 / 16 * Hs_i ** 2 * wp_i ** 3
B_i = wp_i ** 4.
Hs_i is the significant wave height of the primary and the secondary system.
wp_i = 2pi / Tp_i is the angular spectral peak frequency of the primary and the secondary system.
gamma is a peak enhancement factor.
alpha = (1 + 1.1 * log(gamma) ** 1.19) / gamma is a normalizing factor.
sigma is the spectral width parameter (established from experimental data):
- sigma = 0.07 for w <= wp_1
- sigma = 0.09 for w > wp_1

Parameters:

freq (array-like) – Sequence of frequencies to use when generating the spectrum.
freq_hz (bool) – Whether the provided frequencies are in rad/s (default) or Hz.

Notes

The Torsethaugen spectrum is implemented as described in reference [1]. All the intermediate parameters are applied as defined in Table 1 in reference [1].

References