The Dynamics of Local Zones of Turbulized Fluid under the Background Disturbances of Hydrophysical Fields

Voropaeva O. F., Chernykh G. G.

The mathematical models of flat local area of turbulized fluid dynamics in stable stratified medium are constructed. The models are based on a two-dimensional system of averaged equations of hydrodynamics in Oberbeck—Boussinesq approximation, closed with using both differential equations of Reynolds stresses transfer and an algebraic approximations of these quantities. Based on these models the numerical investigation of evolution of flat localized turbulent mixing zone and internal waves generated by it in pycnocline is performed. The numerical model of the interaction of turbulent mixing zone and the local density perturbation in pycnocline is constructed. Numerical simulation of flow is performed in a wide range of parameters of a local density perturbation. It is found that generated by a local density perturbation flow can lead to a significant generation of turbulence energy in turbulent mixing zone and increase the time of its «life». Numerical simulation of the evolution of turbulent mixing zone in a horizontally homogeneous shear flow of linearly stratified fluid was carried out. The data obtained demonstrate the transformation of zone of turbulent perturbations and internal waves generated by it under the influence of shear flow, as well as causing substantial turbulence energy production by the mean flow, which leads to slower decay of turbulence for large time of degeneration.

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