Wave/Potential-Vortex Dynamics within Stratified Shear Layer Turbulence*

We explore the interaction between trapped internal gravity waves on the stratified shear layer dynamics and turbulence following break-down of Kelvin-Helmholtz billows using three-dimensional direct numerical simulations. A weakly inhomogeneous normal-mode decomposition of the fields is proposed, and upon classification of the character of each mode from the mean-flow linear stability analysis, is compared with that of the classic weakly-nonlinear Wave/Potential-Vortex decomposition. This diagnostic tool is finally employed to study the energy transfer among modes and between the propagating wave and turbulent vortex parts, shedding more light on the kinetic and available potential energy evolution.