A novel gas channel experiment is used to study the non-equilibrium development of high Atwood number Rayleigh-Taylor mixing. Two gas streams, one containing air-helium mixture and the other air, flow parallel to each other separated by a thin splitter plate. The streams meet at the end of a splitter plate leading to the formation of an unstable interface and initiation of buoyancy driven mixing. This set up is statistically steady and allows for long data collection times. Here, we describe initial measurements to determine the density profile and growth rate along the mix at low density differences (At ~ 0.05). The facility is however designed capable of large Atwood number studies (At ~ 0.75). Diagnostics include high resolution digital image analysis, which is used to determine the density profile across the mix. The growth parameter (α) is also estimated by a “moving window” calculation. The results are then verified with measurements of α made by a Constant temperature (CT) hot-wire probe and with the growth parameter obtained from small Atwood number experiments (At ~ 0.001). However, there were some inherent errors in the density profile measurements because of non-uniformity in the concentration of smoke. To verify that these errors were indeed measurement errors and not as a result of lack of statistical convergence, a detailed statistical convergence test was performed. It showed that convergence was a direct consequence of the number of different large 3D structures that were averaged over the duration of the run.

Volume Subject Area:
Heat Transfer
Topics:
Density, Errors, Air flow, Buoyancy, Data collection, Equilibrium (Physics), Helium, Probes, Resolution (Optics), Smoke, Temperature, Wire
1.
Chandrasekhar S., Hydrodynamic and Hydromagnetic Stability, Clarendon (1961)
2.
Youngs
 
D. L.
, “
Numerical simulation of turbulent mixing by Rayleigh-Taylor instability
,”
Physica D
, Vol.
12
, pp.
32
–
44
(
1984
)
3.
Beale
 
J. C.
and
Reitz
 
R. D.
 “
Modelling spray atomization with Kelvin-Helmholtz / Rayleigh Taylor hybrid model
,”
Atomiz. Sprays
, Vol.
9
, pp.
623
–
650
(
1999
)
4.
Roberts
 
P. D.
,
Rose
 
S. J.
,
Thompson
 
P. C.
, and
Wright
 
R. J.
,
The Stability of multiple shell ICF Targets
, Vol.
13
, pp.
1980
1980
(
1957
)
5.
Gull
 
S. F.
, “
The X-ray, optical and radio properties of young supernova remnants
,”
Mon. Not. R. Astr. Soc.
, Vol.
171
, pp.
263
–
278
(
1975
)
6.
Taylor
 
G. I.
, “
The instability of liquid surfaces when accelerated in a direction perpendicular to their planes I
,”
Proc. R. Soc. London A
, Vol.
201
, pp.
192
–
196
(
1950
)
7.
Lewis
 
D. J.
, “
The instability of liquid surfaces when accelerated in a direction perpendicular to their planes II
,”
Proc. R. Soc. London A
, Vol.
202
, pp.
81
–
96
(
1950
)
8.
Ratafia
 
M.
, “
Experimental investigation of Rayleigh-Taylor instability
,”
Physics of Fluids
, Vol.
16
, No.
8
, pp.
1207
–
1210
(
1973
)
9.
Read
 
K. I.
, “
Experimental investigation of turbulent mixing by Rayleigh-Taylor instability
,”
Physica D
, Vol.
12
, pp.
45
–
58
(
1984
)
10.
Snider
 
D. M.
and
Andrews
 
M. J.
 “
Rayleigh-Taylor and shear driven mixing with an unstable thermal stratification
,”
Physics of Fluids
, Vol.
6
, No.
10
, pp.
3324
–
3334
(
1994
)
11.
Dimonte
 
G.
and
Schneider
 
M.
, “
Turbulent Rayleigh-Taylor instability experiments with variable acceleration
,”
Phys. Rev. E
, Vol.
54
, pp.
3740
–
3743
(
1996
)
12.
Dalziel
 
S. B.
,
Linden
 
P. F.
, and
Youngs
 
D. L.
,
1999
“
Selfsimilarity and internal structure of turbulence induced by Rayleigh-Taylor instability
,”
J. Fluid Mech.
Vol.
399
, pp.
1
–
48
(1999)
13.
Ramaprabhu
 
P.
and
Andrews
 
M. J.
, “
Experimental investigation of Rayleigh-Taylor mixing at small Atwood numbers
,”
J. Fluid Mech.
, Vol.
502
, pp.
233
–
271
(
2004
)
14.
Hecht
 
J.
,
Alon
 
U.
, and
Shvarts
 
D.
,
Phys. Fluids
, Vol.
6
, pp.
4019
4019
(
1994
)
15.
Glimm
 
J.
,
Saltz
 
D.
, and
Sharp
 
D. H.
,
Phys. Rev. Lett.
, Vol.
80
, pp.
712
–
716
(
1998
).
16.
Cole
 
R. L.
and
Tankin
 
R. S.
, “
Experimental study of Taylor instability
,”
Phys. Fluids
, Vol.
16
, pp.
1810
–
1815
(
1973
)
17.
Read K.I. and Youngs D.L., “Experimental investigation of turbulent mixing by Rayleigh-Taylor Instability,” AWRE Report, No. 001/83 (1983)
18.
Andrews
 
M. J.
and
Spalding
 
D. B.
, “
A simple experiment to investigate two-dimensional mixing by Rayleigh-Taylor instability
,”
Phys. Fluids A
, Vol.
2
, pp.
922
–
927
(
1990
)
19.
Linden P.F., Redondo J.M. and Caulfield C.P., “Molecular mixing in Rayleigh-Taylor Instability,” in Advances in Compressible Turbulent Mixing, edited by Dannevik W.P., Buckingham A.C. and Leith C.E. (U.S. Government Printing Office, Washington D.C.), pp. 95–104 (1992)
20.
Snider
 
D. M.
, and
Andrews
 
M. J.
, “
The simulation of mixing layers driven by compound buoyancy and shear
,”
J. Fluids Engr.
, Vol.
118
, No.
2
, pp.
370
–
376
(
1996
)
21.
Wilson
 
P.
,
Andrews
 
M. J.
, and
Harlow
 
F.
,
1999
“
Spectral non-equilibrium in a turbulent mixing layer
,”
Phys. Fluids A
, Vol.
11
, No.
8
, pp.
2425
–
2433
(1999)
22.
Wilson
 
P. N.
and
Andrews
 
M. J.
, “
Spectral measurements of Rayleigh-Taylor mixing at low-Atwood number
,”
Phys. Fluids A
, Vol.
14
, No.
3
,
938
–
945
(
2002
)
23.
Banerjee A, and Andrews M.J., “Experimental investigation of Statistically Steady Rayleigh-Taylor Mixing at High Atwood Numbers,” FEDSM 2005, Paper # 2005-77154, Houston, TX (2005)
24.
Brown
 
G. L.
and
Roshko
 
A.
, “
On Density Effects and Large Structures in Turbulent Mixing Layers
,”
J. Fluid Mech.
,
64
,
775
775
(
1974
)
25.
Tennekes H. and Lumley J., A First Course in Turbulence, MIT Press, Cambridge, MA (1994)
26.
Snider
 
D. M.
, and
Andrews
 
M. J.
, “
An inexpensive method for quantitative data collection from photographic prints
,”
Meas. Sc. Technol.
,
6
,
502
502
(
1995
)
27.
Wilson P., “A Study of Buoyancy and Shear driven Turbulence within a closed water channel,” Ph.D. Dissertation, Texas A&M University (2002)
28.
Cook
 
A. W.
, and
Dimotakis
 
P. E.
, “
Transition stages of Rayleigh-Taylor instability between miscible fluids
,”
J. Fluid Mech.
,
443
,
69
69
(
2001
)
29.
P.
 
Ramaprabhu
and
M.
 
J. Andrews
, “
Simultaneous measurement of velocity and density in Buoyancy Driven Mixing
,”
Exp. Fluids.
,
34
,
98
98
(
2003
)
30.
Bruun
 
H. H.
, “
Hot-wire corrections in low and high turbulence intensity flows
,”
Journal of Physics E: Scientific Instruments
, Vol.
5
, pp.
812
–
818
(
1972
)
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