In this work we address the problem of ocean acoustic propagation in three dimensions.The problem has not yet be solved completely for a general three dimensional (3-D) ocean enviroment. The work is structured as follows. In section 1 we formulate the problem of acoustic propagation in an ocean waveguide consisting of the acoustic equation and suitable boundary conditions.For better understating of the problem in three dimensions we discuss first the problem in two dimensions in Section 2.We present various methods that have been developted for solving the 2-D problem such as the Ray method,the Integral Transform Solution,Normal Modes and the Parabolic Approximation. In Section 3 we study different approcheas to the 3-D problem based on Normal- Mode theory. In Section 4 we study the method of Parabolic Equation in 3-D introducing several methods of approximations and presenting numrical methods that have been developed for the treatment of the problem such as the SKL model,FOR3D,IMP3D ,PE3D and PECan codes and finally the models of Sturm and Fawcett.In Section 5 we compare the methods of Normal Modes and Parabolic Equation in three dimensions and we discuss the efficiency and restriction of each one of them.
(EN)
University of Crete
