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| Experiment
Description |
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These experiments
generate Richtmyer-Meshkov instability incompressibly by
impulsively accelerating a system of two liquids.
The experimental apparatus consists of a Plexiglas
tank which is mounted to a vertical rail system which
allows it to move freely in the vertical direction. The
bottom half of the tank is initially filled with a salt
solution and the top half with a water/alcohol mixture.
The tank is then lifted to the top of the rail system
and gently oscillated in the horizontal direction to
produce standing internal waves which form a sinusoidal
perturbation on the interface. The tank is then released
allowing it to fall and bounce off of a spring
positioned near the middle of the rails. After bouncing
the tank travels upward and downward on the rails as the
spring is automatically unlocked and removed from its
path. Therefore, when the sled travels down the rails
the second time, it passes the retracted spring and
continues to fall until it is stopped by a shock
absorber positioned at the bottom of the rails. Because
the tank is nearly in free-fall before and after
bouncing, the only body forces the fluids experience are
during the bouncing event, which lasts for approximately
30 ms. Thus the RM instability is generated when the
sled bounces off of the spring and evolves until the
sled impacts the shock absorber.
The flow is visualized in these experiments utilizing
Planar Laser Induced Fluorescence (PLIF) by seeding the
bottom liquid with fluorescein dye and illuminating it
with a sheet of laser light (argon-ion) that passes
through the top of the tank. The fluids are viewed by a
CCD camera that is mounted to the moving container and
which obtains images at a frame rate of 60 Hz. Pictures
below shows a sequence of images from one of these
experiments which shows the development of the
instability from its small amplitude sinusoidal form to
the very symmetrical mushroom pattern that is typical
for this instability when the density difference between
the fluids is relatively small. This very orderly
pattern is abruptly transformed into a very chaotic
turbulent flow when the tank impacts the shock absorber
at the end of its journey. |
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| Experiment
animation |
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File size: 705.17
KBytes
Estimated download time: 275.80 sec at 28.8 Kbps 140.34
sec at 56.6 Kbps
256 Color Palette |
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| Experiment
publications |
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| Jacobs, J.W., and
Sheeley, J.M., "Experimental Study of Incompressible
Richtmyer-Meshkov Instability," Phys. Fluids 8, 405-415,
1996. |
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Jacobs, J.W., and Niederhaus, C.E. "An Experimental
Study of Richtmyer-Meshkov Instability," Proceedings of
the Third Microgravity Fluid Physics Conference,
Cleveland, Ohio, July 1996; NASA Conf. Pub. 3338,
271-276. |
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Jacobs, J.W., and
Niederhaus, C.E., "PLIF Flow Visualization of Single-
and Multi-Mode Incompressible Richtmyer-Meshkov
Instability," Proceedings of the 6th International
Workshop on the Physics of Compressible Turbulent
Mixing, Marseille, France, June 1997, G. Jourdan, and L.
Houas eds., pp. 214-219. |
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Jacobs, J.W., and Niederhaus, C.E. "PLIF Flow
Visualization of Incompressible Richtmyer-Meshkov
Instability," Proceedings of the Fourth Microgravity
Fluid Physics Conference, Cleveland, Ohio, August 1998,
528-533.
File size: 2588 kB |
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Page last updated:
01.01.2006 |
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