Instantaneous vorticity, time averaged kinetic energy and time averaged kinetic energy dissipation rate for oscillatory flows over an isolated ridge.  Images correspond to the near-field "region of interest" (1km x 350m, dx=dz=0.5m) extracted from a truncated domain simulation. The lower right panels indicate where bore-like intense downslope-flow separates from the topography and becomes unstable, leading to shear driven turbulent mixing.
 

Truncated domain simulations can be employed to obtain detailed near-field simulations of the processes governing far-field wave radiation.
 

Critical reflection and abyssal trapping of near-inertial waves on a beta plane (Submitted)

Kraig B. Winters, Pascale Bouruet-Aubertot                     and Theo Gerkema

We consider near-inertial waves continuously excited by a localized source and their subsequent radiation and evolution on a beta plane.

Left: Acoustic backscatter from Knight Inlet. Right: Density from a numerical experiment with similar parameters. Shear instabilities and mixing are responsible for the formation of a stagnant pool of intermediate density fluid (deep blue). In both panels, the flow is accelerating from left to right. The simulation was run using flow_solve with an immersed boundary and captures both the small-scale instabilities and the up-stream propagating wave groups seen in the observations. The small white block near the crest of the sill shows mesh size for the numerical experiment. Only a portion of the computational domain is shown. The pronounced difference in topographic shape between the observations and simulations indicates that the underlying processes are generic and not limited to a specific site.