Modeling of turbulent patches statistical distribution in the stratified ocean layers
Model for the spectrum of density pulsations in a stratified layer of fluid is proposed. It assumes presence of the mechanism vertical turbulent exchange resulting from breaking of the internal waves and formation of the turbulent patches. The mechanism is considered to be quite widespread in many regions of the World Ocean. Modeling implies consideration of two sources of fluctuations: internal waves existing in the whole layer and turbulence concentrated within a certain number of patches distributed within the layer under consideration. The scale ranges of the internal waves and turbulence are partially overlapped; at that the maximum scale of turbulent pulsations is limited by a patch size. Basing on the theory of locally isotropic turbulence and assuming that the oscillations inside a patch are described by harmonic functions, it is shown that their local frequency and local amplitude are connected by the analytical relationship. In the model functions, both the amplitudes and the phases of oscillations are randomized, white noise is added to them. The major features of influence of various specified characteristics of the patches and internal waves upon the spectrum shape are determined. The experimental data have being analyzed by means of the proposed model permit to assess the scales and amount of the patches, as well as the level of turbulence energy in them. The model also exhibits validity of the earlier developed energy approach for defining the scales of turbulent patches.