3-D acoustic scattering from 2-D rough surfaces using a parabolic equation model

dc.contributor.advisorSmith, Kevin B.
dc.contributor.authorHelmy, Ahmed M.
dc.contributor.departmentEngineering Acoustics Academic Committee
dc.contributor.secondreaderKapolka, Daphne
dc.description.abstractRough surface scattering plays a crucial role in the statistics of acoustic propagation signals, especially at mid-frequencies and higher (e.g., acoustic communications systems). For many years, the effects of rough surface scattering were computed using simple models that were applied in two dimensions (2-D) only. A prescribed method of computing 2-D rough surface scattering directly in a parabolic equation model based on the Split-Step Fourier algorithm was introduced by Tappert and Nghiem-Phu in the mid-1980s. This method has been successfully implemented in various 2-D parabolic equation models, including the Monterey Miami Parabolic Equation model. However, some scientific research of more formal scattering predictions have suggested that out-of-plane, three dimensional (3-D) scattering may lead to significant disparities in the scattered field statistics. Introducing a hybrid implementation for the scattering effect in the field transformation equations using a tri-diagonal solution with the Pad approximant to obtain a system of equations for azimuthal corrections will support predictions of the effect of surface scattering on 3-D propagation, which is critical in evaluating the variability in underwater acoustic propagation. Results of the 3-D scattering calculations obtained are compared with the output of basic 2-D interface perturbations utilizing the standard 2-D approach.en_US
dc.description.distributionstatementApproved for public release; distribution is unlimited.
dc.description.serviceLieutenant, Egyptian Naval Forcesen_US
dc.publisherMonterey, California: Naval Postgraduate Schoolen_US
dc.rightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.en_US
dc.subject.authorAcoustic Propagationen_US
dc.subject.authorAcoustic Scatteringen_US
dc.subject.authorSea Surface Perturbationsen_US
dc.subject.authorSplit- Step Fourier Algorithmen_US
dc.subject.authorFinite Difference Algorithm.en_US
dc.title3-D acoustic scattering from 2-D rough surfaces using a parabolic equation modelen_US
etd.thesisdegree.disciplineEngineering Acousticsen_US
etd.thesisdegree.grantorNaval Postgraduate Schoolen_US
etd.thesisdegree.nameMaster Of Science In Engineering Acousticsen_US
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