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Center for Nonlinear Studies |
We present a phenomenological model for the temporal evolution of the probability distribution (PDF) of a tracer advected by a turbulent flow. Our predictions are tested against experimental results. The model mimics the effects of turbulent cascade, that transfers large scales to small scales, until dissipation of fluctuations becomes effective. This is a first step toward a statistical approach of mixing in stratified flow, where the tracer is the density of the fluid. We present a model for the temporal evolution of the PDF of the tracer, and preliminary experimental results on mixing of a two layer fluid by an oscillating grid.
Host: Freddy Bouchet