Hostname: page-component-84b7d79bbc-7nlkj Total loading time: 0 Render date: 2024-07-30T09:09:17.599Z Has data issue: false hasContentIssue false

Acoustic tunnelling*

Published online by Cambridge University Press:  14 November 2011

D. S. Jones
Affiliation:
Department of Mathematics, University of Dundee

Synopsis

General formulae are obtained for the reflection and transmission of harmonic acoustic waves by a curved interface between two media when the frequency is high. In addition to refracted rays there turn up tunnelling rays, if the surface is concave to the source, which are emitted from an evanescent region when the phenomenon of total internal reflection would be anticipated. Uniformly valid formulae dealing with the transition from refraction to tunnelling in both transmission and reflection are derived.

The theory is applied to the circular cylinder and to the top-hat circular jet. In the latter case it is suggested that radiation may tend to be more significant at inclinations of 50°-65° (downstream) and 25°-40° (upstream) to the axis of the cylinder. The augmentation due to tunnelling rays in propagation upstream is mentioned.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1978

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1Born, M.Optik. Springer (1933).CrossRefGoogle Scholar
2Jones, D. S.High-frequency Refraction and Diffraction in General Media. Philos. Trans. Roy. Soc. London Ser. A 255 (1963), 341387.Google Scholar
3Jones, D. S.Acoustics of a splitter plate. J. Inst. Math. Appl, 21 (1978), 197209.CrossRefGoogle Scholar
4Kaminetzky, L. and Keller, J. B.Diffraction coefficients for higher order edges and vertices. SIAM J. Appl. Math. 22 (1972), 109134.CrossRefGoogle Scholar
5Morgan, J. D.The interaction of sound with a subsonic cylindrical vortex layer. Proc. Roy. Soc. London Ser. A 344 (1975), 341362.Google Scholar
6Pryce, M. H. L.The Diffraction of Radio Waves by the Curvature of the Earth. Advances in Phys. 2 (1953), 6795.CrossRefGoogle Scholar
7Roebuck, I. Refraction and Diffraction of High Frequency Waves (Ph.D. Thesis. University of Dundee 1970).Google Scholar
8Roebuck, I.On cylindrical waves in stratified media; high-frequency refraction and diffraction at a plane interface. Proc. Cambridge Philos. Soc. 67 (1970), 133161.CrossRefGoogle Scholar
9Seckler, B. D. and Keller, J. B.The geometrical theory of diffraction in inhomogeneous media. J. Acoust. Soc. Amer. 31 (1959), 206216.CrossRefGoogle Scholar
10Wait, J. R. and Conda, A. M.Pattern of an antenna on a curved lossy surface. Trans. Inst. Radio Engrs AP-6 (1958), 348359.Google Scholar