Create ‘i’ as a vector, and then subscript it and your variables where necessary:
%***********************************
%Begin FOR loop
%***********************************
i=0:P_Res/5000:P_Res;
for k1 = 1:length(i)
if i(k1)<=P_Crit
m_dot(k1)=m_dot_Ch;
else
%Find mach speed of fluid exiting nozzle
M=((2./(gamma-1)).*((P_Res./i(k1)).^((gamma-1)./gamma)-1)).^0.5;
%Find temperature of air exiting nozzle
T_Exit_Norm=T_Res./(1+((gamma-1)./2).*(M.^2)); %(K)
%Find density of air exiting nozzle
rho_Exit_Norm=rho_Res./((1+((gamma-1)./2).*(M.^2)).^(1./(gamma-1))); %(kg/m^3)
%Find speed of sound for the given temperature
a_Exit_Norm=(gamma.*R.*T_Exit_Norm).^0.5; %(m/s)
%Find exit velocity
V_Exit_Norm=M.*a_Exit_Norm; %(m/s)
%Find m-dot
m_dot(k1)=rho_Exit_Norm*V_Exit_Norm*NozArea*((1/100)^2); %(kg/s)
end
P_Ratio(k1)=i(k1)./P_Res;
end
plot(P_Ratio,m_dot,'Color','k');
hold on %Hold plotting until the conclusion
title('Ratio of Back Pressure to Reservoir Pressure vs. Mach Number')
xlabel('Pb / Pr')
ylabel('Mach Number')
hold off
Every instance of ‘i’ in your original code should now be ‘i(k1)’. Check this in the event I missed any.
Also, it’s best not to use ‘i’ or ‘j’ as variables, including loop counters, because MATLAB uses them as its imaginary operators. Using them otherwise causes confusion.
