Turbulent Rayleigh-Taylor instability experiments with variable acceleration

Turbulent mixing due to the Rayleigh-Taylor instability is experimentally found to vary strongly with the temporal acceleration profile g(t). For constant g, the bubble amplitude hb increases as gt² consistent with previous results. For sustained acceleration profiles with dg/dt{≠}0, hb increases, not with the displacement Z={∫}{∫}g dt{'}dt, but with the length S=0.5 [{∫}{}g dt]². For an impulsive acceleration, mixing is minimized with hb{~}Z0.4. These results are used to test mix models. {} 1996 The American Physical Society.