Effects of surface tension on immiscible Rayleigh-Taylor turbulence.

We present phenomenology describing the internal structure of a turbulent zone, produced as the result of the push of a heavy fluid into a light one, for the case of immiscible fluids. One finds that the Kolmogorov cascade is realized within a range that grows with time, viz., scales between the mixing zone width, L proportional variant t(2), and the viscous scale, eta proportional variant t(-1/4). Surface-tension effects lead to formation of an emulsionlike state. Density fluctuations on scales larger than the typical drop size, l, are governed by the Obukhov-Corrsin cascade. If l >> eta, a wave energy cascade, related to capillary waves propagating along the surfaces of drops, is formed at scales below l, l proportional variant t(-2/5).