Comparing Kirchhoff-approximation and boundary-element models for computing gadoid target strengths

KG Foote, David Francis

Research output: Contribution to journalArticle

31 Citations (Scopus)


To establish the validity of the boundary-element method (BEM) for modeling scattering by swimbladder-bearing fish, the BEM is exercised in several ways. In a computation of backscattering by a 50-mm-diam spherical void in sea water at the four frequencies 38.1, 49.6, 68.4, and 120.4 kHz, agreement with the analytical solution is excellent. In computations of target strength as a function of tilt angle for each of 15 surface-adapted gadoids for which the swimbladders were earlier mapped, BEM results are in close agreement with Kirchhoff-approximation-model results at each of the same four frequencies. When averaged with respect to various tilt angle distributions and combined by regression analysis, the two models yield similar results. Comparisons with corresponding values derived from measured target strength functions of the same 15 gadoid specimens are fair, especially for the tilt angle distribution with the greatest standard deviation, namely 16 degrees.
Original languageEnglish
Pages (from-to)1644-1654
Number of pages11
JournalThe Journal of the Acoustical Society of America
Issue number4
Publication statusPublished - 1 Mar 2002


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