function potential_source close all; clear all; x=-10:0.1:10; y=-10:0.1:10; [X,Y] = meshgrid(x,y); Q=1.0; r=sqrt(X.^2+Y.^2); U=1.0; alpha_deg=5; alpha=alpha_deg/180.0*pi; Phi = Q/(2*pi) * log(r); Psi = Q/(2*pi) * atan2(Y,X); contour(Phi,20,'LineColor','red'); hold on; contour(Psi,20,'LineColor','blue'); end