Decay of an axisymmetric vortex with swirl

An exact solution has been obtained for a decaying, viscous axisymmetric vortex with swirl. This has been made possible by assuming a form for the solution. Interestingly a particular value of swirl admits such a solution. Critical points in the flow have been identified in a particular example considered. Analytical nature of the solution allows one to draw conclusions about streamsurfaces and the behaviour of the flow near the critical points. A procedure has been established to ascertain the existence and for a systematic search of closed streamlines in the flow