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AZIMUTHAL LIMITATION IN 3D PE APPROXIMATION FOR UNDERWATER ACOUSTIC PROPAGATION

Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan 106, ROC

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CHI-FANG CHEN

Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan 106, ROC

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MEI-CHUN YUAN

Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan 106, ROC

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, and

YING-TSONG LIN

Department of Engineering Science and Ocean Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd., Taipei, Taiwan 106, ROC

Post Doctor in Woods Hole Oceanographic Institution.

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https://doi.org/10.1142/S0218396X07003317Cited by:4 (Source: Crossref)

Abstract

The azimuthal limitation of the Parabolic Equation (PE) approximation in solving the three-dimensional (3D) wave equation in cylindrical coordinate has been studied in this paper. Typically, 3D problems are dealt with an N × 2D approximation, which treats a 3D field as a fan-like composition of many 2D vertical slices (r - z plane in cylindrical coordinate) ignoring the θ-coupling terms. To deal with problems possessing 3D effects, the θ-coupling terms have to be considered in PE approximation. Nevertheless, the azimuthal limitation in the 3D PE approximation is not defined as well as the vertical angle limitation. Hence, the theoretical derivation estimating the azimuthal limitation is put forth in this work. Numerical results of a modified benchmark problem are also presented to validate the arguments and the wide angle version of the 3D PE model, FOR3D.

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