title: Nonlinear progressive wave equation for stratified atmospheres.
abstract: The nonlinear progressive wave equation (NPE) [McDonald and Kuperman, J. Acoust. Soc. Am. 81, 1406-1417 (1987)] is expressed in a form to accommodate changes in the ambient atmospheric density, pressure, and sound speed as the time-stepping computational window moves along a path possibly traversing significant altitude differences (in pressure scale heights). The modification is accomplished by the addition of a stratification term related to that derived in the 1970s for linear range-stepping calculations and later adopted into Khokhlov-Zabolotskaya-Kuznetsov-type nonlinear models. The modified NPE is shown to preserve acoustic energy in a ray tube and yields analytic similarity solutions for vertically propagating N waves in isothermal and thermally stratified atmospheres.
authors.affiliation: Naval Research Laboratory, 4555 Overlook Avenue Southwest, Washington, D.C. 20375, USA. ed@nova.org
authors.forename: B
authors.initials: B
authors.lastname: Edward McDonald
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Piacsek
mesh_terms: D000162:Acoustics; D001272:Atmosphere; D001274:Atmospheric Pressure; D003198:Computer Simulation; D008432:Mathematical Computing; D017711:Nonlinear Dynamics; D013016:Sound; D013696:Temperature; D013997:Time Factors