Kinetic Energy Transport in the neighborhood of a counter-rotating vortex pair in a stratified and turbulent environment *

We conduct direct numerical simulations (DNSs) of a counter-rotating vortex pair in a stratified, turbulent environment to study the kinetic energy transport in the flow. Special attention is given to how the vortices decay. Two "cascade" processes are identified at moderate and strong flow stratification conditions that quickly destroy the vortex pair. With moderate flow stratification and moderate background turbulence, crow instability leads to vortex reconnection, as suggested by the literature. In an unstratified environment, a vortex ring would form and remain in the flow for a long period of time. At stratified flow conditions, however, a series of subsequent vortex reconnections take place, breaking large vortices into smaller ones. This "cascade" process quickly dissipates the vortices. With strong flow stratification, crow instability cannot cause vortex reconnection, but baroclinic production in the vicinity of the primary vortices gives rise to secondary vortices, and secondary vortices to tertiary vortices, leading to another "cascade" process that quickly dissipates the kinetic energy.