Simulations of hydraulic jumps
This simulation was inspired by Durran (1986, J.
Atmos. Sci.), and was made with the ARPS model. The simulation has
the following properties:
- Two layer atmosphere with more stable layer nearer the ground
- Brunt-Vaisalla frequencies of the lower and upper layers: 0.02 and
0.01
- Depth of lowest layer 2.5 km
- Bell-shaped mountain 500 m high with 10 km half-width
- Horizontal and vertical grid spacings of 1000 and 250 m, respectively
- Initial horizontal wind of 20 m/s, blowing left to right
This combination of environmental parameters
results in a propagating hydraulic jump which forms on the lee (right)
side of the mountain and progresses downstream with time. The figures below depict the situation at 12000
sec (3.33 hr) after simulation start.
Clicking on an image opens an animation of the
field in a new window.
Figure 1: The potential temperature field.
Figure 2: The perturbation horizontal velocity field (the mean initial
wind of 20 m/s has been subtracted out).
Figure 3: The potential temperature field (now colored) with the vertical
velocity contoured (dashed contours are downdrafts).
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Page created January, 2001, by
Robert Fovell
