MOVIES

These animations illustrates the generation of large internal waves downstream of the Knight Inlet sill, British Columbia. The topography and density stratification are taken from observations made by David Farmer and Larry Armi.

Main animations page
1. Case A (0.69MB gif file) Inviscid tidal flow over the Knight Inlet Sill. This case is an inviscid model run. A large overturning wave above the downstream side of the sill creates a thick layer of slow moving fluid. Beneath, a thin downslope jet is formed. This mechanism lies behind the generation of the Chinook winds on the eastern side of the Canadian Rockies. The jet is unstable and strong vortices with associated pulsations in the velocity are created.
2. Case B: (5.0MB gif file) Uses observed density, vertical viscosity/diffusivity at bottom only. Flow separation from near the top of the sill reduces the initial amplitude of the lee wave. The lee wave grows and pushes the separation point down the slope. The strong downslope flow that develops leaves the topography at a hydraulic jump immediately downstream of the lee wave.
3. Case E (2.0MB gif file) This is similar to Case B but uses a different density field. The stratification for depths greater that 20 m has been reduced.
4. Case F (1.8MB gif file) This case is similar to Case E. It uses a Richardson number eddy viscosity/diffusivity parameterization.
5. Case H (0.3MB gif file) This case used a horizontally varying initial stratification and a Richardson number eddy viscosity/diffusivity parameterization.