Consider flow fields with purely tangential motion (circular streamlines): Vr =0 and V =f r . Evaluate

Consider flow fields with purely tangential motion (circular streamlines): Vr =0 and Vθ =f r . Evaluate the rotation, vorticity, and circulation for rigid-body rotation, a forced vortex. Show that it is possible to choose f r so that flow is irrotational, i.e., to produce a free vortex.