| Autor: |
Brind, R. J., Steinberg, R. D., Achenbach, J. D. |
| Zdroj: |
Journal of the Acoustical Society of America; 1982, Vol. 71 Issue S1, pS67-S67, 1p |
| Abstrakt: |
The application of ray theory to the three-dimensional problem of the reflection of curved wavefronts from curved surfaces (arbitrary curvature) is investigated. To assess the accuracy of the short wave approximations, the scattering of time-harmonic longitudinal plane waves by a circular cylindrical cavity and a spherical cavity are considered as special cases. Both the direct ray theory results and the Kirchhoff approximations are examined, but it is found that for reasonable wavelengths the diffracted waves must be taken into account. For the case of a circular cylindrical cavity the creeping waves are evaluated from exact expressions and from asymptotic formulae. A hybrid approach, in which the creeping rays are used to compute the field on the scatterer in the shadow zone, and in which this field is then used in the representation integral, is developed and shown to give good results. The generalizations necessary to deal with scatterers of variable radii of curvature are discussed. The results in the frequency domain are transformed numerically into the time domain, and an example of the application of these methods to the detection of indentations on the surface of a plate is presented. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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