LARGE AND SMALL-SCALE STRUCTURE IN RAYLEIGH-TAYLOR MIXING

Laser-induced fluorescence is used to image the central plane of the m ix region of two immiscible liquids subject to the Rayleigh-Taylor ins tability at an acceleration of 70 times Earth's gravity. The size of t he mixing zone grows with coefficient alpha(b) greater than or similar to 0.054. Individual bubbles are clearly resolved and their structure is measured. The widths of the bubbles are narrower than recent model s predict. An internal structure in the bubbles appears after the mixi ng zone is established. This structure suggests a cascade to small wav elengths. The cascade is required for molecular mix.