Home > wafo > wavemodels > mk87pdf2.m

mk87pdf2

PURPOSE ^

Myrhaug and Kjeldsen (1987) joint (Scf,Hd) PDF.

SYNOPSIS ^

p = mk87pdf2(Hd,Scf,Hs,Tz)

DESCRIPTION ^

 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

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

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

Mathematical Statistics
Centre for Mathematical Sciences
Lund University with Lund Institute of Technology

Comments or corrections to the WAFO group


Generated on Thu 06-Oct-2005 02:21:16 for WAFO by m2html © 2003