Plotting graph by using looping?

Hi,

I have a hard code pasted below: Can anyone help me reducing the amount of lines I have plotted by putting this into loop. I would like to plot nearly 10 curves on the same graph.

Q = 1

Q1 = 9

Q2 = 8

Q3 = 7

Q4 = 6

Q5 = 5

Q6 = 4

Q7 = 3

Q8 = 2

Q9 = 1

depth = Q^(2/3)/(3*(g)^(1/3))

depth1 = Q1^(2/3)/(3*(g)^(1/3))

depth2= Q2^(2/3)/(3*(g)^(1/3))

depth3 = Q3^(2/3)/(3*(g)^(1/3))

depth4 = Q4^(2/3)/(3*(g)^(1/3))

depth5 = Q5^(2/3)/(3*(g)^(1/3))

depth6 = Q6^(2/3)/(3*(g)^(1/3))

depth7 = Q7^(2/3)/(3*(g)^(1/3))

depth8 = Q8^(2/3)/(3*(g)^(1/3))

depth9 = Q9^(2/3)/(3*(g)^(1/3))

A = Wvaries.*depth

A1 = Wvaries.*depth1

A2 = Wvaries.*depth2

A3 = Wvaries.*depth3

A4 = Wvaries.*depth4

A5 = Wvaries.*depth5

A6 = Wvaries.*depth6

A7 = Wvaries.*depth7

A8 = Wvaries.*depth8

A9 = Wvaries.*depth9

V = Q ./ A

V1 = Q1 ./ A1

V2 = Q2 ./ A2

V3 = Q3 ./ A3

V4 = Q4 ./ A4

V5 = Q5 ./ A5

V6 = Q6 ./ A6

V7 = Q7 ./ A7

V8 = Q8 ./ A8

V9 = Q9 ./ A9

plot (Wvaries,V);

hold on

plot (Wvaries,V1);

hold on

plot (Wvaries,V2);

hold on

plot (Wvaries,V3);

hold on

plot (Wvaries,V4);

hold on

plot (Wvaries,V5);

hold on

plot (Wvaries,V6);

hold on

plot (Wvaries,V7);

hold on

plot (Wvaries,V8);

hold on

plot (Wvaries,V9);

hold on

grid on

Answer 1

[Ameer Hamza]

I guess you are trying to do something like this

g = 1;
Wvaries = 1:10;

Q = [1 9 8 7 6 5 4 3 2 1];
depth = Q.^(2/3)./(3*(g).^(1/3));
A = Wvaries.*depth;
V = Q ./ A;

plot (Wvaries, V);

Read about arrays: https://www.mathworks.com/help/matlab/learn_matlab/matrices-and-arrays.html and array operations: https://www.mathworks.com/help/matlab/matlab_prog/array-vs-matrix-operations.html.

[muhammad choudhry]

Hi, I am getting this error!

Matrix dimensions must agree.

Error in matlabhelp (line 9)

A = Wvaries.*depth;

[muhammad choudhry]

So, what I am trying to do here is:

Calculating different depth level on different flowrate.right ? and then using that different depth levels calculating different areas then use them different areas with different flowrate I am calculating different velocities. Once I have them range of velocities I am plotting them V(y-axis) against the Wvaries = [0.50:0.01:1.5] on x-axis..... but I am struggling to plot this using a simple code.

[Ameer Hamza]

There is a plot between three variables: V, Wvaries, and Q. How do you want to plot it? A separate plot for each value of Q or a 3D surface plot?

[muhammad choudhry]

Hi,

Please run a file I attached you, you will get it what is happening here!

I will also ask you If you can help me put the text Inbetween the curves as well. Please see the attached picture as well.

Regards

MSC

[Ameer Hamza]

Following is equivalent to your code.

Fr = 1;
Wvaries = (0.50:0.01:1.5).';
g = 9.81;
Q = 0.1:-0.01:0.01;
depth = Q.^(2/3)/(1.03*(g)^(1/3));
A = Wvaries.*depth;
V = Q ./ A;

ax = axes();
hold on
grid on
plot(Wvaries, V);
x = 1.05;
yline(x,'Color','b','LineStyle','--','LineWidth',1.5)
hold off

Putting text over the line is more complicated. There is no direct function. This shows one method of how it can be done: https://www.mathworks.com/matlabcentral/answers/484490-plot-text-on-line-with-angle

[muhammad choudhry]

Thanks alot for your help!

[Ameer Hamza]

I am glad to be of help!