Can someone please help! I cannot plot this graph. Multiple 3 line graph.

Hi guys, i've tried to plot graph after calculation for 5x3. Unfortunately the graph plotted for last row. When recheck graph data found for 1st and 2nd row shows as 0. But on the output table has all the data.

Please help me fix it.

Only have an error as "add preallocation for speed".

here is the calulated table(Terget is for maximum Pressure)

Here is my graph

>>supposed have to show 3 staright line graph

Table for the graph...collumn 1 and 2 has no data.

here is my code. please help.

clear;

clc;

r = 0.05; %radius in meter

viscosity = [256E-3, 544E-3, 1200E-3, 3680E-3, 5440E-3]; %viscosity in pa.s

l = 0.08; %length in meter

rm = 0.075; %mean radius

N = [1000,3000,4000]; %speed in rpm

sh = 10E-6; %sh in unit meter

fprintf(' ---------------------------------------------------------------------------------------\n');

fprintf(' |Speed (RPM)\tVelocity (m/s)\t\tViscosity (Pa.s)\tMaximum Pressure(MPa) | \n ');

fprintf('---------------------------------------------------------------------------------------\n');

for i = 1:length(N)

u = ((2.*3.142.*N(i))./60)*rm;

for j = 1:length(viscosity)

ho = sh/1.4142;

pm = ((3*u*viscosity(j)*l*sh)/((2*ho)*(sh+ho)*(sh+(2*ho))))/10^6;

fprintf(' | %d\t\t\t%0.6d\t\t\t%0.6d\t\t\t%0.6d\t |\n', N(i), u, viscosity(j), pm);

end

fprintf(' ---------------------------------------------------------------------------------------\n');

end

figure;for i = 1:length(N)

end

u = ((2.*3.142.*N(i))./60)*rm;

for j = 1:length(viscosity)

ho = sh/1.4142;

pm = ((3*u*viscosity(j)*l*sh)/((2*ho)*(sh+ho)*(sh+(2*ho))))/10^6;

viscosity_pm(j,i) = pm;

end

hold on;

for i = 1:length(N)

plot(viscosity, viscosity_pm(:,i), 'DisplayName', ['Speed (RPM) = ',num2str(N(i))]);

end

xlabel('Viscosity (Pa.s)');

ylabel('Maximum Pressure (MPa)'); legend('show');

Answer 1

[VBBV]

clear; 
clc;
r = 0.05; %radius in meter
viscosity = [256E-3, 544E-3, 1200E-3, 3680E-3, 5440E-3]; %viscosity in pa.s 
l = 0.08; %length in meter 
rm = 0.075; %mean radius 
N = [1000,3000,4000]; %speed in rpm 
sh = 10E-6; %sh in unit meter
fprintf(' ---------------------------------------------------------------------------------------\n');

 ---------------------------------------------------------------------------------------

fprintf(' |Speed (RPM)\tVelocity (m/s)\t\tViscosity (Pa.s)\tMaximum Pressure(MPa)  | \n ');

 |Speed (RPM)	Velocity (m/s)		Viscosity (Pa.s)	Maximum Pressure(MPa)  | 
 

fprintf('---------------------------------------------------------------------------------------\n'); 

---------------------------------------------------------------------------------------

for i = 1:length(N)
    u = ((2.*3.142.*N(i))./60)*rm; 
    for j = 1:length(viscosity)
    ho = sh/1.4142;
    pm = ((3*u*viscosity(j)*l*sh)/((2*ho)*(sh+ho)*(sh+(2*ho))))/10^6; 
    fprintf(' | %d\t\t\t%0.6d\t\t\t%0.6d\t\t\t%0.6d\t       |\n', N(i), u, viscosity(j), pm);
    end
fprintf(' ---------------------------------------------------------------------------------------\n'); 
end

 | 1000			7.855000e+00			2.560000e-01			8.280140e+02	       |
 | 1000			7.855000e+00			5.440000e-01			1.759530e+03	       |
 | 1000			7.855000e+00			1.200000e+00			3.881316e+03	       |
 | 1000			7.855000e+00			3.680000e+00			1.190270e+04	       |
 | 1000			7.855000e+00			5.440000e+00			1.759530e+04	       |

 ---------------------------------------------------------------------------------------

 | 3000			2.356500e+01			2.560000e-01			2.484042e+03	       |
 | 3000			2.356500e+01			5.440000e-01			5.278589e+03	       |
 | 3000			2.356500e+01			1.200000e+00			1.164395e+04	       |
 | 3000			2.356500e+01			3.680000e+00			3.570811e+04	       |
 | 3000			2.356500e+01			5.440000e+00			5.278589e+04	       |

 ---------------------------------------------------------------------------------------

 | 4000			3.142000e+01			2.560000e-01			3.312056e+03	       |
 | 4000			3.142000e+01			5.440000e-01			7.038119e+03	       |
 | 4000			3.142000e+01			1.200000e+00			1.552526e+04	       |
 | 4000			3.142000e+01			3.680000e+00			4.761081e+04	       |
 | 4000			3.142000e+01			5.440000e+00			7.038119e+04	       |

 ---------------------------------------------------------------------------------------

figure;
for i = 1:length(N)

u = ((2.*3.142.*N(i))./60)*rm;
for j = 1:length(viscosity)
ho = sh/1.4142;
pm = ((3*u*viscosity(j)*l*sh)/((2*ho)*(sh+ho)*(sh+(2*ho))))/10^6;
viscosity_pm(j,i) = pm;
end
end
viscosity_pm

viscosity_pm = 5×3

1.0e+04 * 0.0828 0.2484 0.3312 0.1760 0.5279 0.7038 0.3881 1.1644 1.5525 1.1903 3.5708 4.7611 1.7595 5.2786 7.0381

hold on; 
for i = 1:length(N)
plot(viscosity, viscosity_pm(:,i), 'DisplayName', ['Speed (RPM) = ',num2str(N(i))]);
end
xlabel('Viscosity (Pa.s)');
ylabel('Maximum Pressure (MPa)'); legend('show');

[VBBV]

you have closed the outer for loop for figures without storing the values for array to be plotted

for i = 1:length(N)
    u = ((2.*3.142.*N(i))./60)*rm;
    for j = 1:length(viscosity)
        ho = sh/1.4142;
        pm = ((3*u*viscosity(j)*l*sh)/((2*ho)*(sh+ho)*(sh+(2*ho))))/10^6;
        viscosity_pm(j,i) = pm;
    end
end  % the end for outer for loop

[Baratganthi Krishnan]

Thank you alot for your quick support. It worked! 🤗🙂