Rankine vortex

A two-dimensional circular flow in which an inner circular region about the origin is in solid rotation:

where V is the tangential speed and r the distance from the origin.
The outer region is free of vorticity, the speed being inversely proportional to the distance from the origin (as in the ‘‘V’’–‘‘R’’ vortex),

This vortex has occasionally been used as a model for the wind distribution in a hurricane.
Milne-Thomson, L. M. 1955. Theoretical Hydrodynamics. 3d ed., . 318–323.