Abstract:

The wide-angle parabolic equation has been used widely to predict a sound field in an ocean with variations in the adiabatic sound speed c. The same equations with c replaced by the effective sound speed c[inf eff]=c+v[inf x] has recently been adopted for calculations of sound propagation in a stratified and/or turbulent atmosphere. Here, v[inf x] is the wind velocity component in the direction from a source to a receiver. However, as is shown in the presentation, such a replacement does not allow one to correctly take into account the effects of the medium velocity v on sound propagation and scattering in a wide-angle approximation. Furthermore, the effects of fluctuations in the density (rho) on sound scattering are also omitted in this approach. In the presentation, a correct wide-angle parabolic equation in media with variations in c, (rho) and v and its Pade (1,1) approximation are derived. The difference in numerical predictions of sound propagation in a stratified and turbulent atmosphere, based on the equation derived and that used previously, is demonstrated. [This material is based upon work supported in part by the U.S. Army Research Office under Contract No. DAAH04-95-1-0593.]