GETJONSWAPPEAKEDNESS Peakedness factor Gamma given Hm0 and Tp for JONSWAP CALL: Gamma = getJonswapPeakedness(Hm0,Tp); Hm0 = significant wave height [m]. Tp = peak period [s] gamma = Peakedness parameter of the JONSWAP spectrum GETJONSWAPPEAKEDNESS relate GAMMA to Hm0 and Tp. A standard value for GAMMA is 3.3. However, a more correct approach is to relate GAMMA to Hm0 and Tp: D = 0.036-0.0056*Tp/sqrt(Hm0); gamma = exp(3.484*(1-0.1975*D*Tp^4/(Hm0^2))); This parameterization is based on qualitative considerations of deep water wave data from the North Sea, see Torsethaugen et. al. (1984) Here GAMMA is limited to 1..7. NOTE: The size of GAMMA is the common size of Hm0 and Tp. Example Hm0 = linspace(1,20); Tp = Hm0; [T,H] = meshgrid(Tp,Hm0); gam = getjonswappeakedness(H,T); contourf(Tp,Hm0,gam,1:7),fcolorbar(1:7) Hm0 = 1:10; Tp = linspace(2,16); [T,H] = meshgrid(Tp,Hm0); gam = getjonswappeakedness(H,T); plot(Tp,gam) xlabel('Tp [s]') ylabel('Peakedness parameter') See also jonswap
Check if all input arguments are either scalar or of common size. | |
Display message and abort function. |
Wave height, Hd, distribution parameters for Stokes waves with Jonswap spectrum. | |
Joint (Scf,Hd) CDF for linear waves with a JONSWAP spectrum. | |
Joint (Scf,Hd) CDF for non-linear waves with JONSWAP spectrum. | |
Joint (Scf,Hd) PDF for nonlinear waves with a JONSWAP spectra. | |
Joint (Scf,Hd) PDF for non-linear waves with a JONSWAP spectra. | |
Joint (Scf,Hd) PDF for linear waves with JONSWAP spectra. | |
Joint (Scf,Hd) PDF for linear waves with a JONSWAP spectrum. | |
Joint (Vcf,Hd) CDF for linear waves with JONSWAP spectrum. | |
Joint (Vcf,Hd) CDF for non-linear waves with JONSWAP spectrum. | |
Joint (Vcf,Hd) PDF for linear waves with a JONSWAP spectrum. | |
Joint (Vcf,Hd) PDF for non-linear waves with a JONSWAP spectrum. | |
Joint (Vcf,Hd) PDF for linear waves with a JONSWAP spectrum. | |
Joint (Vcf,Hd) PDF for linear waves with a JONSWAP spectrum. | |
Wave height, Hd, distribution parameters for Jonswap spectrum. | |
Calculates (and plots) a JONSWAP spectral density |
001 function gam = getjonswappeakedness(Hm0,Tp) 002 %GETJONSWAPPEAKEDNESS Peakedness factor Gamma given Hm0 and Tp for JONSWAP 003 % 004 % CALL: Gamma = getJonswapPeakedness(Hm0,Tp); 005 % 006 % Hm0 = significant wave height [m]. 007 % Tp = peak period [s] 008 % gamma = Peakedness parameter of the JONSWAP spectrum 009 % 010 % GETJONSWAPPEAKEDNESS relate GAMMA to Hm0 and Tp. 011 % A standard value for GAMMA is 3.3. However, a more correct approach is 012 % to relate GAMMA to Hm0 and Tp: 013 % D = 0.036-0.0056*Tp/sqrt(Hm0); 014 % gamma = exp(3.484*(1-0.1975*D*Tp^4/(Hm0^2))); 015 % This parameterization is based on qualitative considerations of deep water 016 % wave data from the North Sea, see Torsethaugen et. al. (1984) 017 % Here GAMMA is limited to 1..7. 018 % 019 % NOTE: The size of GAMMA is the common size of Hm0 and Tp. 020 % 021 % Example 022 % Hm0 = linspace(1,20); 023 % Tp = Hm0; 024 % [T,H] = meshgrid(Tp,Hm0); 025 % gam = getjonswappeakedness(H,T); 026 % contourf(Tp,Hm0,gam,1:7),fcolorbar(1:7) 027 % 028 % Hm0 = 1:10; 029 % Tp = linspace(2,16); 030 % [T,H] = meshgrid(Tp,Hm0); 031 % gam = getjonswappeakedness(H,T); 032 % plot(Tp,gam) 033 % xlabel('Tp [s]') 034 % ylabel('Peakedness parameter') 035 % 036 % See also jonswap 037 038 % Tested on matlab 6.1 039 %History 040 % revised pab 13april2004 041 % -made sure gamma is 1 if Tp/sqrt(Hm0) > 5.1429 042 % by pab 11Jan2004 043 044 error(nargchk(2,2,nargin)) 045 [errorcode,Hm0,Tp] = comnsize(Hm0,Tp); 046 if errorcode > 0 047 error('Requires non-scalar arguments to match in size.'); 048 end 049 x = Tp./sqrt(Hm0); 050 051 gam = ones(size(x)); 052 053 k1 = find(x<=5.14285714285714); 054 if any(k1), %limiting gamma to [1 7] 055 D = 0.036-0.0056*x(k1); % approx 5.061*Hm0^2/Tp^4*(1-0.287*log(gam)); 056 gam(k1) = min(exp(3.484*( 1-0.1975*D.*x(k1).^4 ) ),7); % gamma 057 end 058 return
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