About Evolution of a Single Internal Wave in a Channel. Numerical Experiments

Safray A. S., Tkachenko I. V., Gordeeva S. M.

In this paper an attempt to numerical research of the single internal wave damping process in a channel have been fulfilled to obtain data about wave evolution and factors which influence at damping speed. The second goal of this work consists of investigation of governing system of the model equations nonlinearity influence at numerical solutions/wave evolution, because nonlinear wave interaction often play the primary role in the processes under investigations. Previously, investigation devoted to generation of internal waves by a single surface had been examined by the authors. In the course of it some evaluations of internal wave damping in dependence of mean flow value and stratification, (two-layer and linear) had been obtained. Now, in the course of numerical experiments with 3-D non-hydrostatic finite element model «air-water» supplemented by VOF block, passing of a single internal wave through a channel with different stratification had been simulated. There are a brief description of the model and its numerical algorithm in the paper. Wavelet analysis of numerical simulations results had been used to describe them in the most compact and full form. It was shown that the main role in the internal wave evolution in our experiments plays non-linear three-wave interaction. In the course of it forcing wave and long wave (originated by forcing peculiarities) produce the third long-live wave which assimilates energy of the first two ones. Its damping begins later.

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