Solve MATLAB Source Potential Flow Issues

[physicsCU]

Hey all:

I am trying to plot the streamlines of a source flow in MATLAB. I just have a couple issues. First, when I change the strength, it doesn't appear that the streamlines change at all. Second, the three lines commented out below, I used them from an example, but now they don't work.

If someone could give me a hand checking this code, that would be great.

Code:

clear all
close all
clc

nx = 100; xmin = -2; xmax = 2;
ny = 100; ymin = -2; ymax = 2;
[x y] = meshgrid(linspace(xmin,xmax,nx),linspace(ymin,ymax,ny));
M = 8; xM = 0; yM = 0;
PsiM = (M/(2*pi))*atan2(y - yM,x - xM);
% levmin = PsiM(1,nx);
% levmax = PsiM(ny,nx/2);
% levels = linspace(levmin,levmax,50);
contour(x,y,PsiM,100)
axis([xmin xmax ymin ymax])
xlabel('x'), ylabel('y')
title('Source of Strength M = 4')

 

[physicsCU]

Can anyone help me?

 

[ravenprp]

Hi there,

I can see a few potential issues with your code that may be causing the problems you mentioned. Here are a few suggestions to help you solve them:

1. Make sure you are updating the strength (M) variable in your code before running it again. If you are not changing the strength, the streamlines will not change either.

2. Check the syntax for the atan2 function. It should be atan2(y-yM,x-xM), not atan2(y,x). Also, make sure the xM and yM values are updated to the coordinates of your source.

3. The commented lines that set the contour levels may be causing issues because they are not being used in the code. Try removing them and seeing if that makes a difference.

4. Check the axis limits you have set for your plot. Make sure they are wide enough to capture the streamlines.

I hope these suggestions help you solve the issues you are facing. If you need further assistance, feel free to reach out with specific error messages or screenshots of your plot. Good luck!