In this paper, a new formulation of the Helmholtz equation for sound propagation in a moving inhomogeneous medium in cylindrical coordinates is derived. Based on this formulation, a novel three-dimensional parabolic equation is constructed. This parabolic equation can be used to model sound propagation in an inhomogeneous arbitrary moving medium. The method is used here to simulate three-dimens...

Existence of outflow intrusion introduces small-scale turbulence that perturbs the vertically stratified character of the sound velocity and causes spatial and temporal fluctuations of the sound propagation. In this experimental study, we have investigated acoustic wave propagation with frequency of 50 kHz in a pre-stratified environment with intrusion of a turbulent plume while the si...

We study the propagation of sound in a homogeneous dipolar gas at zero temperature, known as zero sound. We find that below a critical dipolar interaction, undamped sound propagation is possible only in a range of solid angles around the direction of polarization of the dipoles. For larger interaction strength, zero sound propagates in all directions, but its nature changes as a function of dir...