Acoustic field generated by moving sources in stratified waveguides

We investigate sound propagation from moving sources in stratified waveguides, both completely composed of fluids and with a solid top layer. Asymptotic formulas are derived for the acoustic field generated by a narrow-band point source moving non-uniformly either in a waveguide or on its surface. The asymptotic formulas, expressed in terms of retarded times and Doppler-shifted frequencies, are very simple and suitable for numerical computations. They take into account normal modes and lateral wave contributions and they have clear physical interpretations. Numerical results are presented to illustrate the effects of source motion, in particular, mode cutoff and Doppler effects.