New approach to the normal mode method in underwater acoustics

A new approach to the numerical solution of normal mode problems in underwater acoustics is presented, in which the corresponding normal mode problem is transformed to the problem of solving a dynamic system. Three applications are considered: (1) the broad band normal mode problem; (2) the range-dependent problem with perturbation proportional to the range parameter; and (3) the evolution of the normal mode with environmental parameters. A numerical simulation for a broad band problem is performed, and the calculated eigenvalues have good agreement with those obtained by the standard normal mode code KRAKAN.