  We investigate numerically the Navier-Stokes dynamics of reconnecting vortex
rings at small $Re$ number. We find that reconnections are dissipative due to
the smoothing of vorticity gradients at reconnection kinks and to the formation
of secondary structures of stretched anti-parallel vorticity which transfer
kinetic energy to small scales where it is subsequently dissipated efficiently.
In addition, the relaxation of the reconnection kinks excites Kelvin waves
which due to strong damping are of low wavenumber and affect directly only
large scale properties of the flow.

Fluid Dynamics