DIFFRACTION EFFECTS IN THE PROPAGATION OF COMPRESSIONAL WAVES IN THE ATMOSPHERE
Abstract
Asymptotic methods are used to find approximate solutions of the acoustic wave equation in a medium where the velocity is a continuously variable function of one coordinate. It is shown that, when the velocity function has a minimum, undamped normal mode solutions exist, and that such solutions are closely analogous to the internally reflected waves in the case of a medium made up of discrete layers. By converting the sum of the high-order normal modes into an equivalent integral, it is shown that superposition of these modes leads to geometrical ray theory modified by diffraction in a manner that may be computed from the incomplete Fresnel and Airy integrals. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1950
- Accession Number
- AD0638147
Entities
People
- Norman A. Haskell
Organizations
- Air Force Cambridge Research Laboratories