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Open Alexis Nicolas Gomel requested to merge master into main
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function [h,k,sigma,cg,cp,lambda,nu,alpha,alpha4,beta,gamma,mu,Dys_hilb,muintexp] = Dysthe_HONLSparameters(omega,kh,x,FOD)
%%
% input params
% omega is the angular frequency in units of g^{1/2}
% hk is the current value of h(x)k(x)
% x is the position along the propagation distance
%
% output params
% k(x) wavenumber
% sigma = tanh(kh)
% cg = group velocity
% cp = phase velocity
%
% The shoaling is trivial, see Djordjevic&Redekopp ZAMP 1978
% muintexp is the exp of the integral of mu(x) exp(int(mu))
%
% The parameters are defined as in Sedletsky JETP Lett. 97, 180-193 (2003)
% where the envelope of the surface elevation is used and the expansion
% to fourth order is performed
%
% lambda = group velocity dispersion
% alpha = third order dispersion (=0 in the limit of deep water)
% alpha4 = fourth order dispersion
% nu = cubic nonlinear coefficient
% beta = coefficient of |A|^2 D_t A
% gamma = coefficient of A D_t |A|^2
%
% Dysthe according to Debbie's thesis.
%%
% auxiliary quantities
% sigma = tanh(kh);
% k = omega.^2./sigma;
sigma=1;
h=1000;
g=1;
k = omega.^2;
% h = kh.*sigma./omega^2;
% group and phase speed
cp = omega./k;
cg = 0.5.*cp;
Dys_hilb=2*k.^3/omega;
% nu in the paper
sigma2 = (2*omega*cg).^2 - 4 .* kh .* sigma;
sigmaq = sigma.^2-1;
% mu in the paper
sigma3 = sigmaq.^2.*kh - sigma.*(sigma.^2-5);
% NLS quantities
% beta''/2 = omega''/Cg^3/2
lambda = omega./(8.*k.^2); %checked
% THIS FORMULA IS NOT CORRECT!!!
% alphaT = -omega'''/6
% changing to space evolution
% TOD
% beta3/6 = alphaT/cg^4 - 2*lambda^2*cg
% FOD
% beta4/24
% TBC
% TBC !!!!!!!
if FOD ~=0
alpha4 = -1./(3*128*omega.^7.*cg.^7).*h.*sigmaq.*(...
- 3*kh.^4.*sigmaq.^4.*(1-5.^kh) ...
- 4.*kh.^sigma.^3.*sigmaq.*(1-kh.*sigma).*(3-4*kh.*sigma).*(5-8.*kh.*sigma)...
- 4.*kh.^3.*sigma.*sigmaq.^3.*(15+kh.*sigma.*(-31+24.*kh.*sigma))...
+ sigma.^4.*(-3 + kh.*sigma.*(39+8.*kh.*(-7+2*kh.*sigma)))...
+ 6.*kh.^2.*sigma.^2.*sigmaq.^2.*(-19+kh.*sigma.*(51+4*kh.*sigma.*(-11 + 4.*kh.*sigma))));
else
alpha4 = zeros(size(kh));
end
% cubic nonlinearity
nu = (omega.*k.^2)./2;
beta=3.*(omega.*k)./2;
gamma=(omega.*k)./4;
% shoaling (depth-related loss/amplification)
mu = (1-sigma.^2).*(1-kh.*sigma)./(sigma+kh.*(1-sigma.^2));
muintexp = ((2.*kh + sinh(2*kh))./cosh(kh).^2).^0.5;
alpha = 0;
% lambda = lambda.*ON_OFF_coef(1);
% nu = nu.*ON_OFF_coef(2);
% alpha = alpha.*ON_OFF_coef(3);
% beta = beta.*ON_OFF_coef(4);
% gamma = gamma.*ON_OFF_coef(5);
end
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