A transfer of a tracer in decaying turbulent layer

Abstract

A mixing of a passive tracer inside a turbulent layer generated by a localized short-time perturbation is studied numerically. Two cases of initial distribution of the tracer are considered: two-layer and continuous with constant gradient. It is shown that, regardless of details of initial fields of a turbulent energy and dissipation in the layer, a tracer concentration goes with time to self-similar regimes. Distributions of the concentration inside the layer are found to be substantially nonuniform, with a ratio of concentration gradient in the middle of the layer to initial gradient about 0.5.