TY - JOUR
T1 - Limits of the potential flow approach to the single-mode Rayleigh-Taylor problem
AU - Ramaprabhu, P.
AU - Dimonte, Guy
AU - Young, Yuan Nan
AU - Calder, A. C.
AU - Fryxell, B.
PY - 2006
Y1 - 2006
N2 - We report on the behavior of a single-wavelength Rayleigh-Taylor flow at late times. The calculations were performed in a long square duct (λ×λ×8λ), using four different numerical simulations. In contradiction with potential flow theories that predict a constant terminal velocity, the single-wavelength Rayleigh-Taylor problem exhibits late-time acceleration. The onset of acceleration occurs as the bubble penetration depth exceeds the diameter of bubbles, and is observed for low and moderate density differences. Based on our simulations, we provide a phenomenological description of the observed acceleration, and ascribe this behavior to the formation of Kelvin-Helmholtz vortices on the bubble-spike interface that diminish the friction drag, while the associated induced flow propels the bubbles forward. For large density ratios, the formation of secondary instabilities is suppressed, and the bubbles remain terminal consistent with potential flow models.
AB - We report on the behavior of a single-wavelength Rayleigh-Taylor flow at late times. The calculations were performed in a long square duct (λ×λ×8λ), using four different numerical simulations. In contradiction with potential flow theories that predict a constant terminal velocity, the single-wavelength Rayleigh-Taylor problem exhibits late-time acceleration. The onset of acceleration occurs as the bubble penetration depth exceeds the diameter of bubbles, and is observed for low and moderate density differences. Based on our simulations, we provide a phenomenological description of the observed acceleration, and ascribe this behavior to the formation of Kelvin-Helmholtz vortices on the bubble-spike interface that diminish the friction drag, while the associated induced flow propels the bubbles forward. For large density ratios, the formation of secondary instabilities is suppressed, and the bubbles remain terminal consistent with potential flow models.
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U2 - 10.1103/PhysRevE.74.066308
DO - 10.1103/PhysRevE.74.066308
M3 - Article
AN - SCOPUS:33845757621
SN - 1063-651X
VL - 74
JO - Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
JF - Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics
IS - 6
M1 - 066308
ER -