SeaSwellFun

[Hm0,Hm0sea,Hm0swell,Tp,Tpsea,Tpswell,fp,fseparation,f,Syy]=SeaSwellFun(input,fs,duration,nfft,h,fmin,fmax,ftailcorrection,tailpower,fminswell,fmaxswell,mincutoff,maxcutoff,tailcorrection,dispout)

DESCRIPTION

Separate sea wave from swell wave

INPUT

input=importdata(‘h.mat’);

Load water depth (h)/surface elevation (Eta) data and rename it “input” in (m)

fs=10;

Sampling frequency that data collected at in (Hz)

duration=1024;

Duration time that data collected in input in each burst in second

nfft=2^10;

NFFT for Fast Fourier Transform

h=1;

Mean water depth in (m)

fmin=0.04;

Minimum frequency for cut off the lower part of spectra

fmax=1;

Maximum frequency for cut off the upper part of spectra

ftailcorrection=1;

Frequency that diagnostic tail apply after that (typically set at 2.5fm, fm=1/Tm01)

tailpower=-4;

Power that diagnostic tail apply based on that (-3 for shallow water to -5 for deep water)

fminswell=0.1;

Minimum frequency that is used for Tpswell calculation

fmaxswell=0.25;

Maximum frequency that swell can have, It is about 0.2 in Gulf of Mexico

mincutoff=’off’;

Define if to cut off the spectra below fmin

mincutoff=’off’: Cutoff off

mincutoff=’on’: Cutoff on

maxcutoff=’off’;

Define if to cut off the spectra beyond fmax

maxcutoff=’off’: Cutoff off

maxcutoff=’on’: Cutoff on

tailcorrection=’off’;

Define if to apply diagnostic tail correction or not

tailcorrection=’off’: Not apply

tailcorrection=’jonswap’: JONSWAP Spectrum tail

tailcorrection=’tma’: TMA Spectrum tail

dispout=’on’;

Define to display outputs or not (‘off’: not display, ‘on’: display)

OUTPUT

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)

fp

Peak Wave Frequency (Hz)

f

Frequency (Hz)

fseparation

Sea and Swell Separation Frequency (Hz)

Syy

Wave Surface Elevation Power Spectrum (m^2s)

EXAMPLE

[Hm0,Hm0sea,Hm0swell,Tp,Tpswell,fp,fseparation,f,Syy]= SeaSwellFun(input,10,1024,2^10,1.07,0.05,2,0.9,-4,0.1,0.25,'on','on','off','on');

NOTES

In case that data are measured by a pressure sensor, data should be corrected for pressure attenuation. In that case, function “PcorFFTFun.m” or “PcorZerocrossingFun.m” should be called first to correct pressure (water depth) data before calculating wave properties. Results from either of those functions can be imported to this function for spectral analysis of wave parameters. If provided “RunOceanlyz.m” file is used, it will do this procedure if proper input parameters are selected in “oceanlyzinput.m” file. Please read the note in “PcorFFTFun.m”.

This function can be used as a standalone command in Matlab/GNU Octave command line or it can be embedded in Matalb/GNU Octave script file (.m file) as:

[Hm0,Hm0sea,Hm0swell,Tp,Tpsea,Tpswell,fp,fseparation,f,Syy]=SeaSwellFun(input,fs,duration,nfft,h,fmin,fmax,ftailcorrection,tailpower,fminswell,fmaxswell,mincutoff,maxcutoff,tailcorrection,dispout);

Example for using a provided sample input file:

[Hm0,Hm0sea,Hm0swell,Tp,Tpswell,fp,fseparation,f,Syy]= SeaSwellFun(input,10,1024,2^10,1.07,0.05,2,0.9,-4,0.1,0.25,'on','on','off','on');