Abstract

Modeling of the Hydroacoustic Source for Global Ocean Tomography

V.V.Kovalevsky (Institute of Computational Mathematics and Mathematical Geophysics, SB RAS, Novosibirsk, Russia)

e-mail: vvkov@opg.sscc.ru

The paper deals with the modeling of the resonant source of the hydroacoustic waves of infrasonic frequency range for global ocean acoustic tomography problems. Estimates have shown, that for the allocation of waves at distances about 1000-10000 km it is necessary to radiate a significant wave energy - about 1000 kWh in a low- frequency range 1-5 Hz. Such wave energy can be supplied by the vibrating sources with very high force characteristics - about 10-100 thousand tons. In the paper is consided a resonance scheme of the infrasonic source for liquid, containing nonlinear oscillatory contour and ensuring the direct compensation of an imaginary part of the medium impedance. The model of the hydroacoustic vibrational source includes a gasfilled resonance radiator operated under the free surface of the liquid. It is shown that for the effective radiation of the acoustic waves in the infrasonic frequency range two conditions must be carried out. First of them defines the depth of immersing of the radiator taking into account the influence of reflected wave from free surface on the full wave field. The second condition connected with the dependence of the resonant frequency of the gasfilled radiator from its size and gas pressure from the depth of immersing. The combination of these conditions allowed us to define the main parameters of a radiators for the superpower vibrators and to show the opportunity of creation of resonant sources with power 100-500 kW in the frequency range 1-5 Hz.

Section : 6