Plotting the solution of multi-variable non-linear equations (solved using fsolve).
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These are the equations:
function [fval]= ptfunc(X)
Tcell=X(1);
Pcell=X(2);
Qh=X(3);
Pteg=X(4);
alpha = 0.95;
A = (0.04)^2;
epsilon = 0.88;
sigma = 5.69*10^(-8);
Ta = 298.15;
u=(0.003+1/5)^-(1);
ns = 0.10;
theta = 0.0011;
An=6.4*10^-7;
Hn=0.01;%:0.01:0.06;
N=62;
S=185*10^-6;
rho=10^-5;
den=2*rho;
k=1.5;
Z=(S^2)/(rho.*k);
Tc=298;
r=0.2;
n=0.0001;
hc=0.00009;
num2=2*r*hc;
G=500;
fval(1,1)= -Qh+ alpha*G*A-u*A*(Tcell-Ta)-epsilon*sigma*A*((Tcell.^4)-(Ta^4))-Pcell;
fval(2,1)= -Pcell+ alpha*G*A*ns.*(1-theta.*(Tcell - 298));
fval(3,1)= -Qh + (k*An*N/Hn)*(1-Z*(3*Tcell+Tc)/8)*(Tcell-Tc);
fval(4,1)= -Pteg+(S^2)*An*N*((Tcell-Tc)^2)./(den.*(n+Hn).*(1+num2./Hn).^2);
I need to plot the varaibles with respect to G. How do I do that?
2 个评论
Stephan
2019-4-9
G is a scalar - its value is 500 - so you would plot 4 single points - one for each result from fsolve. Is this what you want to do?
Yavar Hayat
2019-4-9
采纳的回答
Torsten
2019-4-9
0 个投票
function main
G = linspace(250,750).';
X0 = [1,1,1,1];
for i=1:numel(G)
sol = fsolve(@(X)ptfunc(X,G(i)),X0);
x(i,:) = sol;
X0 = sol;
end
plot(G,x(:,1))
end
function fval = ptfunc(X,G)
Tcell=X(1);
Pcell=X(2);
Qh=X(3);
Pteg=X(4);
alpha = 0.95;
A = (0.04)^2;
epsilon = 0.88;
sigma = 5.69*10^(-8);
Ta = 298.15;
u=(0.003+1/5)^-(1);
ns = 0.10;
theta = 0.0011;
An=6.4*10^-7;
Hn=0.01;%:0.01:0.06;
N=62;
S=185*10^-6;
rho=10^-5;
den=2*rho;
k=1.5;
Z=(S^2)/(rho.*k);
Tc=298;
r=0.2;
n=0.0001;
hc=0.00009;
num2=2*r*hc;
%G=500;
fval(1,1)= -Qh+ alpha*G*A-u*A*(Tcell-Ta)-epsilon*sigma*A*((Tcell.^4)-(Ta^4))-Pcell;
fval(2,1)= -Pcell+ alpha*G*A*ns.*(1-theta.*(Tcell - 298));
fval(3,1)= -Qh + (k*An*N/Hn)*(1-Z*(3*Tcell+Tc)/8)*(Tcell-Tc);
fval(4,1)= -Pteg+(S^2)*An*N*((Tcell-Tc)^2)./(den.*(n+Hn).*(1+num2./Hn).^2);
end
4 个评论
Yavar Hayat
2019-4-9
Torsten
2019-4-9
plot(G,x)
instead of
plot(G,x(:,1))
Walter Roberson
2019-4-10
However, it is working. The reason it does not look like it is working is that one of the results is on the order of 300, and two of them are on the order of 0.1, and the last of them is on the order of 0.01 . You simply cannot see anything in 3 of the 4 lines because they are insignificant on the scale of the first plot.
You could use subplot() to break the values out.
If you have a new enough MATLAB you could use stackedplot()
Yavar Hayat
2019-4-10
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