Investigation of the Effect of the Baric Formation Parameters on Free and Forced Oscillations of the Level and Flow in the Sea of Azov
L.V. Cherkesov, T.Ya. Shul’ga |
Marine Hydrophysical Institute, Russian Academy of Sciences, Sevastopol, Russian Federation |
E-mail: shulgaty@mail.ru |
Abstract
The effect of inhomogeneous moving atmospheric pressure fields upon the flows, and free and forced oscillations of the Azov Sea level induced by constant wind is studied by the method of mathematical modeling. The hypothesis on the role of the resonance mechanism in arising of the extremely high amplitudes of the surge oscillations and seiches generated by a baric field moving at the velocity equal to that of a free long wave is tested. The equations of the applied mathematical model are described in general, transition to the curvilinear coordinates is shown, the model parameters chosen allowing for different physical factors are substantiated, and the features of the model numerical realization are explained. The information on the wind and atmospheric pressure fields used in the numerical experiments is given. The results of simulations of free oscillations in the Sea of Azov are discussed with the purpose to analyze the impact of the resonance characteristics related to the speed and time of the baric fields’ motion over the sea. The sea level deviations resulted from the calculations with constant pressure and those with passing of the inhomogeneous baric front are compared. It is revealed that at one and the same wind, the baric disturbances moving over the Sea of Azov induce the forced oscillations and after their forcing is stopped – free oscillations the amplitudes of which exceed those obtained at constant atmospheric pressure by 14%. It is shown that the baric front motion, speed and time of which are chosen based on the assumption on generation of the waves with maximum amplitudes, plays an important but not decisive role in formation of the currents’ structure and the level oscillations in the Sea of Azov.
Keywords
the Sea of Azov, sigma-coordinate model, free oscillations of liquid, seiches, stationary currents, storm surges, nodal lines, atmospheric front, free long wave velocity.
DOI: 10.22449/1573-160X-2016-4-12-24