7. Consider the complex velocity potential 2(2) k log(z zo) where k is real and zo is a complex constant. Find the corresponding velocity potential and stream function. Show that the velocity is purely radial relative to the point z-zo, and sketch the flow configuration. Such a flow is called a "source" if k > 0 and a "sink" if k 0. Sketch the flow configuration. The strength of this flow, called a point vortex, is defined to be M Vals, where VO is the velocity in the circumferential direction and ds is the increment of arc length in the direction tangent to the circle C. Show that M -2rk. (See also Subsection 2.1.2.) 7. Consider the complex velocity potential 2(2) k log(z zo) where k is real and zo is a complex constant. Find the corresponding velocity potential and stream function. Show that the velocity is purely radial relative to the point z-zo, and sketch the flow configuration. Such a flow is called a "source" if k > 0 and a "sink" if k 0. Sketch the flow configuration. The strength of this flow, called a point vortex, is defined to be M Vals, where VO is the velocity in the circumferential direction and ds is the increment of arc length in the direction tangent to the circle C. Show that M -2rk. (See also Subsection 2.1.2.)