MK87PDF2 Myrhaug and Kjeldsen (1987) joint (Scf,Hd) PDF. CALL: f = mk87pdf2(Hd,Scf,Hs,Tz) f = pdf structure evaluated at meshgrid(Scf,Hd) Hd = zero down crossing wave height Scf = crest front steepness Hs = significant wave height. Tz = average zero down crossing period. MK87PDF2 returns the joint PDF of (Scf, Hd) given Hs and Tz, i.e., crest front steepness (2*pi*Ac/(g*Td*Tcf)) and wave height, given the seastate. The root mean square values of Hd and Scf (Hrms,Erms) are related to the significant waveheight and the average zero down crossing period by: Hrms = 0.715*Hs; Erms = 0.0202+0.826*Hs/(Tz^2); Example: Hs = 7;Tz=10; h = linspace(0,3*Hs)'; s = linspace(0,3*Hs/Tz^2)'; f = mk87pdf2(h,s,Hs,Tz); pdfplot(f) See also mk87pdf, createpdf
PDF class constructor | |
Myrhaug and Kjeldsen (1987) joint (Scf,Hd) PDF. | |
Calculates quantile levels which encloses P% of PDF | |
Display message and abort function. | |
X and Y arrays for 3-D plots. |
001 function p = mk87pdf2(Hd,Scf,Hs,Tz) 002 %MK87PDF2 Myrhaug and Kjeldsen (1987) joint (Scf,Hd) PDF. 003 % 004 % CALL: f = mk87pdf2(Hd,Scf,Hs,Tz) 005 % 006 % f = pdf structure evaluated at meshgrid(Scf,Hd) 007 % Hd = zero down crossing wave height 008 % Scf = crest front steepness 009 % Hs = significant wave height. 010 % Tz = average zero down crossing period. 011 % 012 % MK87PDF2 returns the joint PDF of (Scf, Hd) given Hs and Tz, 013 % i.e., crest front steepness (2*pi*Ac/(g*Td*Tcf)) and wave height, given 014 % the seastate. The root mean square values of Hd and Scf (Hrms,Erms) are 015 % related to the significant waveheight and the average zero down 016 % crossing period by: 017 % Hrms = 0.715*Hs; 018 % Erms = 0.0202+0.826*Hs/(Tz^2); 019 % 020 % Example: 021 % Hs = 7;Tz=10; 022 % h = linspace(0,3*Hs)'; 023 % s = linspace(0,3*Hs/Tz^2)'; 024 % f = mk87pdf2(h,s,Hs,Tz); 025 % pdfplot(f) 026 % 027 % See also mk87pdf, createpdf 028 029 % References: 030 % Myrhaug, D. and Kjelsen S.P. (1987) 031 % 'Prediction of occurences of steep and high waves in deep water'. 032 % Journal of waterway, Port, Coastal and Ocean Engineers, Vol. 113, pp 122--138 033 % 034 % Myrhaug & Dahle (1984) 035 % 'Parametric modelling of joint probability density 036 % distributions for steepness and asymmetry in deep water waves' 037 % 038 039 % tested on: matlab 5.1 040 % history: 041 % revised pab 09.08.2003 042 % Changed input + updated help header 043 % revised pab 01.04.2001 044 % -added example 045 % revised pab 08.02.2000 046 % - 047 % by Per A. Brodtkorb 1998 048 049 error(nargchk(3,4,nargin)) 050 051 if nargin < 4|isempty(Tz), Tz = 8; end 052 if nargin < 3|isempty(Hs), Hs = 6; end 053 054 p = createpdf(2); 055 056 [X,Y] = meshgrid(Scf,Hd); 057 p.f = mk87pdf(Y,X,Hs,Tz); 058 p.x{1}=Scf(:); 059 p.x{2}=Hd(:); 060 p.labx{1}='Crest front steepness'; 061 p.labx{2}='Wave height [m]'; 062 063 p.title='Myrhaug and Kjeldsen (1987) density of crest front steepness and wave height.'; 064 065 [p.cl p.pl]=qlevels(p.f,[10:20:90 95 99 99.9]); 066
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