Chapter 4, Problem 4.25P

An incompressible flow in polar coordinates is given by

$v_r=K\cos \theta \left(1-\frac{b}{r^2}\right)$

$v_{\theta }=K\cos \theta \left(1-\frac{b}{r^2}\right)$

Does this field satisfy continuity? For consistency, what should the dimensions of constants K and b be? Sketch the surface where v_r= 0 and interpret.