Description
This
test case is provided for you to check your code before
running the assigned problem and configuration for
Computer Problem 5.Please note the settings below, and remember to change all settings back to the official problem(s) before running and handing in results.
- This is a pressure gradient/buoyancy forces test, only.
- You will disable advection and diffusion (of U, W, Theta) for this test.
- Grid layout: 201x41; ∆x=∆z=100 meters
- Quasi-compressible sound speed Cs = 100 meters/sec
- Integration: time step ∆t = 0.25 sec, run for 200
steps (T=50 seconds)
- Initial U, W, and P' = 0 (as in real problem)
- Initial T field: one temperature perturbation only, center (x,z) = (10050, 2050) meters, magnitude -25 degrees K (2nd perturbation magnitude = 0 deg. K)
- Potential temperature perturbation radius (x,z) = 4000, 1000
Test case results
- Plots for time steps 0-10 use contour intervals of: 0.005 (U), 0.100 (W), 1.0 (T), 1.0 (P')
- Plots for time steps 20-200 use contour intervals:
0.5 (U), 0.5 (W), 1.0 (T), 25.0 (P')
| step | Theta' | U | W | P | notes | |
|---|---|---|---|---|---|---|
| N=0 |  |
zero | zero | zero | initial condition note theta' field does not change in this test. |
|
| 1 |  |
zero |  |
 |
T'<0 causes W<0; nonzero W at (n+1) time causes dP'/dz |
|
| 2 |  |
still zero |
 |
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W and dP'/dz increase in magnitude. u' remains zero since dp'/dx term is at (n-1) |
|
| 3 |  |
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dP'/dx => U develops |
|
| 4 |  |
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 |
 |
All increase in magnitude. P' has clear pattern, but not symmetry in magnitude, due to density. |
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| 5 |  |
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| 6 |  |
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| 7 |  |
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| 8 |  |
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U contours finally appear, now that |U| > 0.005 |
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| 9 |  |
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Note symmetry in U field (about X center; not in Z, due to density differences) |
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| 10 |  |
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| 20 |  |
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Note contour interval change |
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| 60 |  |
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| 100 |  |
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| 200 |  |
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