kh_calc.m

 % kh_calc
function kh = kh_calc(Td,depth);
%
%  Calculate wave number from Wave period and depth
%
% RL Soulsby (2006) "Simplified calculation of wave orbital velocities"
% HR Wallingford Report TR 155, February 2006
%
g = 9.81;
omega=2.0*pi/Td;
x=omega^2.0*depth/g;
%
if(x<1.0);
    y=sqrt(x);
else
    y=x;
end
%
% Iteratively solving 3 times for eqn.7 of Soulsby 1997 by using
% eqns. (12a-14)
%
t=tanh(y);
cff=(y*t-x)/(t+y*(1.0-t*t));
y=y-cff;
%
t=tanh(y);
cff=(y*t-x)/(t+y*(1.0-t*t));
y=y-cff;

t=tanh(y);
cff=(y*t-x)/(t+y*(1.0-t*t));
y=y-cff;
kh=y;
%
return
end % function kh_calc