scientimate.donelanpsd

f, Syy, Hm0, fp, Tp, Tm01, Tm02 = scientimate.donelanpsd(U10=10, F=10000, fp=0.33, fs=2, N=256, CalSpectralSP='yes', dispout='no')

Description

Calculate Donelan spectrum (power spectral density), (Donelan et al. 1985)

Inputs

U10=10

Wind velocity at 10 meter above surface level in (m/s)

F=10000

Wind fetch length in (m)

fp=0.33

Peak wave frequency (fp=1/Tp) in (Hz)

If CalSpectralSP=’yes’; then fp is calculated from U10 and F

fs=2

Sampling frequency that data collected at in (Hz)

N=256

Total number of points between 0 and fs-df, where df=fs/N

Spectrum is reported between 0 and fs/2 with total number of points equal to (N/2+1)

Total number of points between 0 and fs is (N+1)

CalSpectralSP=’yes’

Define to calculate spectral shape parameters or not (‘yes’: calculate, ‘no’: use given parameters by user)

dispout=’no’

Define to display outputs or not (‘yes’: display, ‘no’: not display)

Outputs

f

Frequency (Hz)

Syy

Wave Energy Power Spectrum (m^2/Hz)

Hm0

Zero-Moment Wave Height (m)

fp

Peak wave frequency (Hz)

Tp

Peak wave period (second)

Tm01

Wave Period from m01 (second), Mean Wave Period

Tm02

Wave Period from m02 (second), Mean Zero Crossing Period

Examples

import scientimate as sm
f,Syy,Hm0,fp,Tp,Tm01,Tm02=sm.donelanpsd(10,10000,0.33,2,256,'yes','yes')

References

Donelan, M.A.; Hamilton, J., and Hui, W., 1985. Directional spectra of wind-generated waves. Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, 315(1534), 509–562.