scientimate.seaswell1d#
fseparation, Hm0, Hm0sea, Hm0swell, Tp, Tpsea, Tpswell, m0, m0sea, m0swell, fp, Tm01, Tm02 = scientimate.seaswell1d(f, Syy, fsepCalcMethod='hwang', fu=0.5, fmaxswell=0.2, fpminswell=0, Windvel=10, dispout='no')
Description#
Partition (separate) wind sea from swell in a power spectral density using an one dimensional method
Inputs#
- f
Frequency (Hz)
- Syy
Power spectral density (m^2/Hz)
- fsepCalcMethod=’hwang’
- Wind sea swell separating calculation method‘celerity’: using deep water wave celerity, ‘gilhousen’: Gilhousen and Hervey (2001),‘hwang’: Hwang et al. (2012), ‘exact’: calculate exact value
- fu=0.5
An upper bound of a spectrum integration frequency (Hz)
- fmaxswell=0.25
Maximum frequency that swell can have, It is about 0.2 in Gulf of Mexico
- fpminswell=0.1
A lower bound of a spectrum (minimum frequency) that is used for Tpswell calculation
- Windvel=10
Wind velocity (m/s), only required for Gilhousen and Hervey (2001) method
- dispout=’no’
Define to display outputs or not (‘yes’: display, ‘no’: not display)
Outputs#
- fseparation
Wind sea and Swell Separation Frequency (Hz)
- Hm0
Zero-Moment Wave Height (m)
- Hm0sea
Sea Zero-Moment Wave Height (m)
- Hm0swell
Swell Zero-Moment Wave Height (m)
- Tp
Peak wave period (second)
- Tpsea
Peak Sea period (second)
- Tpswell
Peak Swell Period (second)
- m0
Zero-Moment of the power spectral density (m^2)
- m0sea
Zero-Moment of the wind sea spectrum (m^2)
- m0swell
Zero-Moment of the swell spectrum (m^2)
- fp
Peak wave frequency (Hz)
- Tm01
Wave Period from m01 (second), Mean Wave Period
- Tm02
Wave Period from m02 (second), Mean Zero Crossing Period
Examples#
import scientimate as sm
import numpy as np
N=2**11 #Total number of points
fs=2 #Sampling frequency
df=fs/N #Frequency difference
f=np.arange(0,fs/2+df,df) #Frequency vector
f[0]=f[1]/2 #Assign temporarily non-zero value to fisrt element of f to prevent division by zero
SyySea=0.016*9.81**2/((2*np.pi)**4*(f**5))*np.exp(-1.25*(0.33/f)**4) #Calculating Spectrum
SyySwell=0.016*9.81**2/((2*np.pi)**4*(f**5))*np.exp(-1.25*(0.15/f)**4)*0.005 #Calculating Spectrum
Syy=SyySea+SyySwell
f[0]=0
Syy[0]=0
fseparation,Hm0,Hm0sea,Hm0swell,Tp,Tpsea,Tpswell,m0,m0sea,m0swell,fp,Tm01,Tm02=sm.seaswell1d(f,Syy,'exact',0.5,0.3,0,10,'yes')
References#
Gilhousen, D. B., & Hervey, R. (2002). Improved estimates of swell from moored buoys. In Ocean Wave Measurement and Analysis (2001) (pp. 387-393).
Hwang, P. A., Ocampo-Torres, F. J., & García-Nava, H. (2012). Wind sea and swell separation of 1D wave spectrum by a spectrum integration method. Journal of Atmospheric and Oceanic Technology, 29(1), 116-128.