3D Polar Plot

Dear MathWorks comunity,
I want to plot a function containing two variables: r and phi.

sigma and a are constants, I want to display sigma x dependent of r and phi in an polar diagramm like the one shown below.

I really tried to find a soulution by myself (polarplot3d for example), but I couldnt find a way and my colleagues didnt knew either. It seems like an easy task for someone who knows what to do. I would be happy if someone could help me out.
best wishes
Paul from Germany

Answer 1

[Torsten]

a = 1.0;
sigma = 2.0;
r = 0.2:0.001:3;
phi = 0:pi/100:2*pi;
[R,PHI] = meshgrid(r,phi);
X = R.*cos(PHI);
Y = R.*sin(PHI);
SIGMAx = sigma*sqrt(a./(2*R)).*cos(PHI/2).*(1-sin(PHI/2).*sin(3/2*PHI));
contourf(X,Y,SIGMAx)

[Paul Schütz]

Thank you so much! That solved my problem :)

[Torsten]

I think I forgot a "sigma":

SIGMAx = sigma*sqrt(a./(2*R)).*cos(PHI/2).*(1-sin(PHI/2).*sin(3/2*PHI)) - sigma;

instead of

SIGMAx = sigma*sqrt(a./(2*R)).*cos(PHI/2).*(1-sin(PHI/2).*sin(3/2*PHI));

Answer 2

[Bjorn Gustavsson]

A quick search on the file exchange leads to these submissions:pcolor-in-polar-coordinates, 3d-polar-plot and polar-contour-plot. Most likely one of those will be (very close to) what you want, from there you should be able to modify to suit your need.

HTH

[Paul Schütz]

Thank you too :)