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Introduction Forcings Observations Atmospheric Turbulence Ocean Turbulence Dimensional Analysis Basic Equations Length Scales. Convective flows, Rayleigh-Nuselt numbers. Important parameters to consider in unstableflows Rayleigh Taylor Instab. The Atwood Number, A - PowerPoint PPT Presentation
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1. Introduction2. Forcings3. Observations4. Atmospheric Turbulence5. Ocean Turbulence6. Dimensional Analysis7. Basic Equations 8. Length Scales
Convective flows, Rayleigh-Nuselt numbers
Important parameters to consider in unstableflows Rayleigh Taylor Instab.
• The Atwood Number, A
• The width of the mixing zone,
• The non-dimensional time,
• The Fractal Dimension
21
21
²cgAt2
tH/Ag
/logNlog
D
N D
1
1
Boussinesq Aproximation consiss
On neglegting inertial accelerations on
density fluctuations, but allowing the
Gravitational accelerations.
Baroclinic Vorticity
Shocks in AIR of He and Kr Balls, Which is Which ?
0 500 1000 1500
0
5
10
15
20
25
ODCi
tir #260 tir #262 tir #265point 1 point 2 point 3 point 4
x [c
m]
t [µs]
x3x4
x2
x1 krypton M=1, 2
0 500 1000 1500 20000
100
200
300
UODC
i
= 370 m/s Uec
= 45 m/s
U [m
/s]
t [µs]
tir #296 tir #257 tir #254point 1 point 2 point 3 point 4
x4 x1x2x3hélium
M=1,05
0 5 100
1
2
M = 1,05 < 5% M = 1,2 < 5% M = 1,5 < 5% M = 1,7 < 5%
L aval/R
0
t/t0
a)b)c)d)
VelocityMagnitude
Volumeof Fluid
VorticityMagnitude
0÷10÷0,33 -106÷84
min
max
Basic Turbulence
Basic Turbulence
Basic Turbulence
Basic Turbulence
• Stratification causes strong vertical anisotropy!• Redondo(1990)