jonswappsd#
[f, Syy, Hm0, fp, Tp, Tm01, Tm02] = jonswappsd(U10, F, fp, fs, N, gama, CalSpectralSP, dispout)
Description#
Calculate JONSWAP spectrum (power spectral density), (Hasselmann et al. 1973)
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
- gama=3.3;
Peak enhancement parameter (between 1 and 7)
- fs=2;
Sampling frequency that data collected at in (Hz)
- N=256;
Total number of points between 0 and fs that spectrum reports at 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#
[f,Syy,Hm0,fp,Tp,Tm01,Tm02]=jonswappsd(10,10000,0.33,2,256,3.3,'yes','yes');
References#
Hasselmann, K.; Barnett, T. P.; Bouws, E.; Carlson, H.; Cartwright, D. E.; Enke, K.; Ewing, J. A.; Gienapp, H.; Hasselmann, D. E.; Kruseman, P.; Meerbrug, A.; Muller, P.; Olbers, D. J.; Richter, K.; Sell, W., and Walden, H., (1973). Measurements of wind-wave growth and swell decay during the Joint North Sea Wave Project (JONSWAP). Deutsche Hydrographische Zeitschrift A80(12), 95p.