Abstract
The three-dimensional Rayleigh-Taylor instability is studied in a low Atwood number (A≈0.15) miscible fluid system. The two fluids are contained within a Plexiglas tank that is mounted on vertical rails and accelerated downward by a weight and pulley system. A net acceleration between 13 and 23m/s2 can be maintained, resulting in an effective body force equivalent to 0.33-1.35 times Earth's gravity. A single-mode, three-dimensional perturbation is produced by oscillating the tank, which has a square cross section, along its diagonal. Early time measured growth rates are shown to have good agreement with linear stability theory. At late time, the instability exhibits a nonconstant vertical interfacial velocity in agreement with the recent numerical computations of Ramaprabhu [Phys. Rev. E 74, 066308 (2006)]. Both the late-time bubble and spike velocities have values greater than those predicted by both the simple buoyancy-drag model developed by Oron [Phys. Plasmas 8, 2883 (2001)] and the potential flow model of Goncharov [Phys. Rev. Lett. 88, 134502 (2002)]. The disagreement with the models can be attributed to the formation of vortices, in this case vortex rings, observed in the experiments but not accounted for by the models.
Original language | English (US) |
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Article number | 124102 |
Journal | Physics of Fluids |
Volume | 19 |
Issue number | 12 |
DOIs | |
State | Published - Dec 2007 |
ASJC Scopus subject areas
- Computational Mechanics
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Fluid Flow and Transfer Processes