Recent advances in the turbulent Rayleigh-Taylor instability

In the turbulent Rayleigh-Taylor instability, the light fluid penetrates the heavy fluid as bubbles with a diameter D-b and amplitude h(b) that grow self-similarly D-b proportional to h(b)similar to alpha(b)A gt(2) where A is Atwood number, g is acceleration, and t is time. Experiments measure an acceleration constant alpha(b)similar to 0.04-0.08 whereas the highest resolution three-dimensional numerical simulations obtain alpha(b)similar to 0.02-0.03 with idealized initial conditions. This paper reconciles this apparent discrepancy with new simulations that quantify the importance of initial conditions on alpha(b). The results compare favorably with experiments and a model based on self-similar bubble dynamics. (c) 2005 American Institute of Physics.