Turbulent-layer dynamics in homogeneous and stratified fluids

The dynamics of a layer of turbulence excited by a ribbed oscillating grate in homogeneous and stratified fluids is investigated experimentally. The time dependences of the thickness of the region encompassed by turbulence in a homogeneous fluid are obtained. On the basis of a semiempirical turbulence theory, it is shown that the time dependence of the coordinate of the turbulent-front position can be described by a power function. A satisfactory agreement between the experimental and theoretical dependences is obtained. Different regimes of turbulent-layer dynamics in a fluid with salinity stratification are investigated. The results of numerical calculations of turbulent-layer dynamics in a stratified fluid that satisfactorily agree with experimental data are presented. The data obtained can be used to estimate the efficiency of mixing within the oceanic depth.