THE INTEGRAL SOLUTION OF THE SOUND FIELD IN A MULTILAYERED LIQUID-SOLID HALF-SPACE WITH NUMERICAL COMPUTATIONS FOR LOW-FREQUENCY PROPAGATION IN THE ARCTIC OCEAN.

摘要

The report develops by matrix methods the integral solution of the wave equation for point sources of harmonic waves in a liquid layer of a multilayered liquid-solid half space in a form convenient for numerical computation on a high-speed digital computer. Only the case is considered of a high-speed liquid bottom underlying the stack of layers. The integral over wave number has singularities in the integrand and is conveniently transformed into the complex plane. By a proper choice of contours,complex poles are displaced to an unused sheet of the two-leaved Riemann surface,and the integral solution for the multilayered system reduces to a sum of normal modes plus the sum of two integrals,one along the real axis and the other along the imaginary axis. Both integrals are evaluated by a Gaussian quadrature formula. Sample computations are presented for low-frequency propagation in the Arctic Ocean sound channel. These are preliminary computations and the ice layer,which averages three meters in thickness,is not included in the layered system. The effects of the ice layer on propagation are currently under investigation. (Author)