Prediction of a body's structural impedance and scattering properties using correlation of random noise

TitlePrediction of a body's structural impedance and scattering properties using correlation of random noise
Publication TypeJournal Article
Year of Publication2013
AuthorsRakotonarivo S.T, Kuperman WA, Williams E.G
JournalJournal of the Acoustical Society of America
Date Published2013/12
Type of ArticleArticle
ISBN Number0001-4966
Accession NumberWOS:000328654100021
Keywordsequivalent sources; field acoustic holography; fluid; ocean; shells; sound-scattering

This paper derives a method to estimate the structural or surface impedance matrix (or equivalently the inverse of the structural Green's function) for an elastic body by placing it in an encompassing and spatially random noise field and cross-correlating pressure and normal velocity measurements taken on its surface. A numerical experiment is presented that utilizes a cross-correlation method to determine the structural impedance matrix for an infinite cylindrical shell excited by a spatially random noise field. It is shown that the correlation method produces the exact analytic form of the structural impedance matrix. Furthermore, using standard impedance formulations of the scattered and incident pressure fields at the object surface that are based on the equivalent source method and using this estimated structural impedance, a prediction of the scattered acoustic field at any position outside of the object can be made for any given incident field. An example is presented for a point (line) source near a cylindrical shell and when compared with the analytical result, excellent agreement is found between the scattered fields at a radius close to the shell. (C) 2013 Acoustical Society of America.

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