Point Vortex Flow Around a Cylinder

The vector field
        Overscript[v, ⇀] = γ/(2π) (-y/(x^2 + y^2), x/(x^2 + y^2)) defined for (x^2 + y^2)^(1/2) ≥R
represents point vortex flow around a cylinder. The equations of our streamlines then are
        x ' (t) = γ/(2π) -y(t)/(x^2(t) + y^2(t)),
        y ' (t) = γ/(2π) x(t)/(x^2(t) + y^2(t)).
We can plot the equipotential curves and streamlines as follows.

Needs["Graphics`PlotField`"] Needs["Graphics`ImplicitPlot`"] ɯ ... ange {{-3R, 3R}, {-3R, 3R}}}], ]}], ;,         }]