Friedlander-Keller ray expansions and scalar wave reflection at canonically-perturbed boundaries

Tew, R.H.

Abstract

This paper concerns the reflection of high-frequency, monochromatic linear waves of wavenumber k (>>1) from smooth boundaries which are O (k-1/2) perturbations away from either a specified near-planar boundary or else from a given smooth, two-dimensional curve of general O(1) curvature. For each class of perturbed boundary, we will consider separately plane and cylindrical wave incidence, with general amplitude profiles of each type of incident field.
This interfacial perturbation scaling is canonical in the sense that a ray approach requires a modification to the standard WKBJ 'ray ansatz' which, in turn, leads to a leading-order amplitude (or 'transport') equation which includes an extra term absent in a standard application of the geometrical theory of diffraction ('GTD'). This extra term is unique to this scaling, and the afore-mentioned modification that is required is an application of a generalised type of ray expansion first posed by F G Friedlander and J B Keller [1].

Citation

Tew, R. (2019). Friedlander-Keller ray expansions and scalar wave reflection at canonically-perturbed boundaries. European Journal of Applied Mathematics, 30(1), 1-22. https://doi.org/10.1017/S0956792517000353

• Journal Article Type: Article
• Acceptance Date: Nov 24, 2017
• Online Publication Date: Jan 4, 2018
• Publication Date: 2019-02
• Deposit Date: Nov 29, 2017
• Publicly Available Date: Jan 4, 2018
• Journal: European Journal of Applied Mathematics
• Print ISSN: 0956-7925
• Electronic ISSN: 1469-4425
• Publisher: Cambridge University Press
• Peer Reviewed: Peer Reviewed
• Volume: 30
• Issue: 1
• Pages: 1-22
• DOI: https://doi.org/10.1017/S0956792517000353
• Keywords: Geometrical theory of diffraction (GTD); ray theory; WKBJ-method; wave asymptotics; linear waves; asymptotic methods; high-frequency scattering
• Public URL: https://nottingham-repository.worktribe.com/output/903545
• Publisher URL: https://www.cambridge.org/core/journals/european-journal-of-applied-mathematics/article/friedlanderkeller-ray-expansions-and-scalar-wave-reflection-at-canonically-perturbed-boundaries/BAD0FA4F8AA5BEEC48F91BFD7CA362E9
• Additional Information: This article has been published in a revised form in European Journal of Applied Mathematics, [http://doi.org/10.1017/S0956792517000353]. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works. © copyright holder.