why doesn't this matlab code work? HELP!!!
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Erika Abril
le 6 Mar 2021
Commenté : Walter Roberson
le 7 Mar 2021
My problem is that this code doesn't work and I need the graph. Help please.
clear all
clc;
es=0.007;%m
d=2800;%kg/m^3
k=180;%W/m K
E=0.8;
C=900;%J/kg K
Tamb=298;%K
As=0.04;%m^2
qh=12500; %W/m^2 K
h=10;%W/m^2 K
Tfp=408;%K
cteEB=5.67*10^-8;
V=0.00028;%m^3
to=0;
deltat=0.1;% seconds
t=[];
Tf=[];
while (Tfp>=Tf)
Tf(i+1)=(As/(d*C*V))*(qh-(h*(Tf(i)-Tamb))-(E*cteEB*(Tf(i)^4-Tamb^4)))*deltat+Tf(i);
t(i+1)=t(i)+deltat;
hold on
plot(Tf,t);
i=i+1;
end
xlabel ('Temperature');
ylabel ('Time [s]');
2 commentaires
John D'Errico
le 6 Mar 2021
PLease do not provide a PICTURE of your code. That makes it virtually impossible for someone to easily help you, because they need to then type in your code by reading the code and then transcribing it character by character into MATLAB. And why would you possibly want to make it more difficult to get help?
Réponse acceptée
Walter Roberson
le 6 Mar 2021
Modifié(e) : Walter Roberson
le 7 Mar 2021
You did not initialize i so it will have its default value of sqrt(-1). Then inside the loop when you assign to Tf(i+1) that is a destination of 1+1i which is not a valid index.
For that code to work you need to initialize i to 1.
1 commentaire
Walter Roberson
le 7 Mar 2021
Tf=[];
while (Tfp>=Tf)
You initialize Tf to empty. When you compare Tfp to empty, the result is false, so your while loop never executes.
Plus de réponses (1)
Basil C.
le 6 Mar 2021
The error could be in the while loop. Try using the following.
while(Tfp>=Tf(end))
If you could share the error, it would be more helpful
2 commentaires
Walter Roberson
le 6 Mar 2021
Oddly enough in this particular loop testing the entire vector is not the problem, though testing an entire vector is often a problem.
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