Acoustic Scattering 1 Acoustic fields 1 Acoustic wave propagation 1 Alternating directions 1 Boundary-fitted grid 1 Circular waveguides Future applications 1 Galerkin methods 1 Helmholtz operators 1 Numerical methods 1 Parabolic Equations 1 Partial differential equations 1 Surface waters 1 Three dimensional computer graphics 1 Threedimensional (3-d) 1 Underwater acoustics 1 Underwater sound propagation 1 article 1 human 1 seashore 1 sound 1