title: Numerical comparison of acoustic wedge models, with application to ultrasonic telemetry.
abstract: Ultrasonic telemetry imaging systems are used to monitor such immersed structures as main vessels of nuclear reactors. The interaction between acoustic beams and targets involves scattering phenomena, mainly specular reflection and tip diffraction. In order to assist in the design of imaging systems, a simulation tool is required for the accurate modeling of such phenomena. Relevant high-frequency scattering models have been developed in electromagnetic applications, in particular, the geometrical optics (GO), Geometrical Theory of Diffraction (GTD) and its uniform corrections (UAT and UTD), Kirchhoff approximation (KA) and Physical Theory of Diffraction (PTD). Before adopting any of them for simulation of scattering of acoustic waves by edged immersed rigid bodies, it is important to realize that in acoustics the characteristic dimension to the wave length ratio is usually considerably smaller than in electromagnetics and a further study is required to identify models' advantages, disadvantages and regions of applicability. In this paper their numerical comparison is carried out. As the result, the most suitable algorithm is identified for simulating ultrasonic telemetry of immersed rigid structures.
authors.affiliation: M2M China, 6F, West Building, La De Fang Si, 1480 Tianfu Avenue, Chengdu, Sichuan 610041, PR China; CEA, LIST, Department of Imaging & Simulation for Nondestructive Testing, F-91191 Gif-sur-Yvette, France; LUNAM Université, Université du Maine, CNRS UMR 6613, Laboratoire d'Acoustique de l'Université du Maine, Le Mans, France; Fédération Acoustique du Nord Ouest (FANO), FR CNRS 3110, France. Electronic address: b.lu@m2m-ndt.com.
authors.forename: B
authors.initials: B
authors.lastname: Lü
authors.affiliation: CEA, LIST, Department of Imaging & Simulation for Nondestructive Testing, F-91191 Gif-sur-Yvette, France. Electronic address: michel.darmon@cea.fr.
authors.forename: M
authors.initials: M
authors.lastname: Darmon
authors.affiliation: Sound Mathematics Ltd., Cambridge CB4 2AS, UK. Electronic address: l.fradkin@soundmathematics.com.
authors.forename: L
authors.initials: L
authors.lastname: Fradkin
authors.affiliation: LUNAM Université, Université du Maine, CNRS UMR 6613, Laboratoire d'Acoustique de l'Université du Maine, Le Mans, France; Fédération Acoustique du Nord Ouest (FANO), FR CNRS 3110, France. Electronic address: catherine.potel@univ-lemans.fr.
authors.forename: C
authors.initials: C
authors.lastname: Potel
keywords: Acoustic scattering models; Geometrical Theory of Diffraction; Kirchhoff approximation; Physical Theory of Diffraction; Ultrasonic telemetry