Development and Research of Turbulent Exchange Semi-empirical Models for Vortex Resolution Methods Using Expedition Data

The article studies and calibrates semi-empirical models of turbulent exchange for the Azov Sea using expedition data for vortex-resolving methods. To solve the problem of constructing adequate models of vortex resolution, the data obtained during the expedition in the Central-Eastern part of the Azov Sea were used. The hydrophysical ADCP probe was used to measure the three-dimensional velocity vector of the water medium. The measured water flow currents fields were filtered using box, Gauss and Fourier filter with different filter widths. In these calculations, the filter width was set based on the dimension of the hydrodynamics problem to be solved and the grid scale corresponding to this dimension. Then, using filtered data, the parameterization of the vertical turbulent exchange coefficient was carried out. Parameterization of the turbulent exchange process in discrete for the vertical coordinate direction is performed on the basis of subgrid models. To assess the quality of parametrization, an analysis was carried out using methods of mathematical statistics and quality functional. The optimal parameterization is selected. The modeling of the velocity vector of the aqueous medium obtained as a result of the application of the RANS and LES approaches is carried out. The key differences of modeling results are revealed. The analysis of the influence of regular waves on the turbulent vertical exchange is presented.