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 h(b) increases as gt(2) consistent with previous results. For sustained acceleration profiles with dg/dt not equal 0, hb increases, not with the displacement Z=integral integral g dt'dt, but with the length S=0.5 [integral root g dt](2). For an impulsive acceleration, mixing is minimized with h(b) similar to Z(0.4). These results are used to test mix models.