Internal Waves and Rotating Turbulence

Many natural systems in which waves and turbulence interact---including oceans, atmospheres, liquid-metal planetary cores, and stars---are also rotating. Rotation modifies the properties of internal waves, as well as turbulence. Here we study the interaction of rotating turbulence and internal waves by analyzing 3D simulations of a turbulent convective layer adjacent to a stably-stratified layer. The convection is driven by internal heating, and we run simulations with a range of rotation rates corresponding to different convective Rossby numbers. When rotation and gravity are aligned with each other (i.e., near the pole), we find the convective turbulence excites internal waves in the stratified layer in the same way independent of Rossby number. The only effect of rotation is to place a lower limit on the allowed wave frequencies. The picture is more complicated when rotation and gravity are perpendicular (i.e., near the equator). In this case, the rotating turbulence is more efficient at exciting waves, provided the simulations are sufficiently turbulent that the convection three-dimensionalizes at small scales. Finally, we will compare these simulations results to heuristic theories of rotating convection and wave generation.