New to matlab problem plotting

Hello guys! I'm new to matlab and i have to make a 3D plot. I have managed to do that for a 2D graph (like a cross-sectional view) and tried searching for hours on how can i make it a 3D shape but without any luck. I have attached the code i wrote for the 2D version as well as pics of how it looks like and how it's supposed to look like. I hope you can give me some insight on how to do it.

t=linspace(0,2*pi);
r=1.1;
xc=-0.1;
yc=0.05;
x=r*cos(t)+xc;
y=r*sin(t)+yc;
plot(x,y)
axis equal
zeta=x+i*y;
z=zeta+1./zeta; hold on; plot(-1,0,'rs',1,0,'gd'); plot (real(z),imag(z))

Answer 1

[Star Strider]

See: how to convert 2D graph to 3D? for one approach.

The second image looks as though it was copied from my Answer in that post!

[Silviu Coman]

Hello, I'm sorry for using your picture but it was exactly what i was looking for in order to explain what i am trying to do. In terms of the end result, your post is exactly what i needed, however i have to use the joukowsky problem in order to make the airfoil shape. This is the exercise: "Using the Joukowsky transform draw a "wing" by adding the third dimension to the curve. The wing should be "horizontal" (the profile is defined in the Oxz axis) and span on the y axis.". Once again i am a complete beginner with matlab and from what i understood from searching online, the joukowsky transformation is a way to make an airfoil shape from a circle. As i said, i hope i didn't upset you by using your post and i hope you can make me understand this a little bit better.

[Star Strider]

See if this does what you want:

t=linspace(0,2*pi);
r=1.1;
xc=-0.1;
yc=0.05;
x=r*cos(t)+xc;
y=r*sin(t)+yc;

figure
plot(x,y)
axis equal
zeta=x+i*y;
z=zeta+1./zeta; hold on; plot(-1,0,'rs',1,0,'gd'); plot (real(z),imag(z))

figure
hs = surf([real(z);real(z)], [imag(z);imag(z)], [0; 10]*ones(size(z)), 'EdgeColor','none');
rotate(hs, [1 0 0], 90)
axis equal
set(gca, 'Color','none', 'GridAlpha',0, 'XColor','none', 'YColor','none', 'ZColor','none')  % Experiment With These Options

producing:

Aerospace engineering is not an area of my expertise. (The closest I can gget to it is being an Instrument-Rated Private Pilot.) I have no idea of what the Joukowsky transform is or what it does, so I cannot help you with that part.

[Silviu Coman]

Thank you very much for your help, it's exactly what i needed. I understood what you did except in 2 places. Would you mind trying to explain in the simplest way you can what these two parts do?

[0; 10]*ones(size(z))  %1
and
rotate(hs, [1 0 0], 90)  %2

[Star Strider]

My pleasure!

(I was away for an hour attendng an on-line Medical Grand Rounds on artificial intelligence in disease characterisation. Definitely interesting, and relevant to the MATLAB Deep Learning Toolbox functions that I need to become more experienced with.)

First:

[0; 10]*ones(size(z))  %1

creates a vector that has a value of 0 in the first row and a value of 10 in the second row, in order to create the necessary depth (here, wing length) to plot the surface object. Vary the values in the [0; 10] vector to see how it works. Using that same idea, the surf call could be re-coded as:

hs = surf([1;1]*real(z), [1;1]*imag(z), [0; 10]*ones(size(z)), 'EdgeColor','none');

with the same result.

Second:

rotate(hs, [1 0 0], 90)  %2

uses the rotate function to rotate the wing from its original vertical orientation to a horizontal orientation. Again, vary the last 2 arguments to get different results and to see how it works.

.

[Star Strider]

If my Answer helped you solve your problem, please Accept it!

.

[Silviu Coman]

Ok, got it. Once more, thank you for clearing this up and i hope you have a great day!

[Star Strider]

As always, my pleasure!

You, too!