Linear and nonlinear acoustic wave propagation in the atmosphere

This paper describes the investigation of the acoustic wave-propagation theory and numerical implementation for the situation of an isothermal atmosphere. A one-dimensional model to validate an asymptotic theory and an axisymmetric three-dimensional situation to relate to a realistic situation are considered. In addition, nonlinear wave propagation and the numerical treatment are included. It is known that the gravitational effects play a crucial role in the low-frequency acoustic wave propagation. They propagate large distances and, as such, the numerical treatment of those problems becomes difficult in terms of posing boundary conditions that are valid for all frequencies. Our treatment is discussed in detail. Open questions are posed.