%Oil Mixture
% Coded by NFR on 1.24.2019
% This is another example of local functions
% Also shows how to pass parameters
%
close all
clc
nu_a = 3.8; %centistokes
nu_b = 13.9; %centistokes
X = linspace(0,1,1000); % Mass fraction of A
Nu_Mix_Refutas = VBNcalc2(nu_a,nu_b,X);
plot(X,Nu_Mix_Refutas)
hold on
Nu_Mix_Gambill = GambillModel(nu_a,nu_b,X);
plot(X,Nu_Mix_Gambill)
hold off
xlabel('Mol Fraction A')
ylabel('Kinematic Viscosity')
legend('Refutas Method','Gambill Method')

% Define the local function for Gambill
function Nu_mix = GambillModel(nu_a,nu_b,X)
    Nu_mix = (X*(nu_a)^(1/3)+(1-X)*(nu_b)^(1/3)).^3;
end



% This is the local function for Refutas
function VBNcomp = VBNcalc(nu)
    VBNcomp = 14.534*log(log(nu+.8))+10.975;
end

function Nu_mix = VBNcalc2(nu_a,nu_b,X) % X is mass component of a
    VBN_1 = VBNcalc(nu_a);
    VBN_2 = VBNcalc(nu_b);
    VBNmix = X*VBN_1+(1-X)*VBN_2;
    Nu_mix = exp(exp((VBNmix-10.975)/14.534))-0.8;
end