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dc.contributor.authorRavetta, Patricio A.en_US
dc.date.accessioned2014-03-14T20:19:56Z
dc.date.available2014-03-14T20:19:56Z
dc.date.issued2005-11-28en_US
dc.identifier.otheretd-12072005-113549en_US
dc.identifier.urihttp://hdl.handle.net/10919/29975
dc.description.abstractA novel concept in noise control devices for landing gears is presented. These devices consist of elastic membranes creating a fairing around the major noise sources. The purpose of these devices is to reduce wake interactions and to hide components from the flow, thus, reducing the noise emission. The design of these fairings was focused on the major noise sources identified in a 777 main landing gear. To find the major noise sources, an extensive noise source identification process was performed using phased arrays. To this end, phased array technologies were developed and a 26%-scale 777 main landing gear model was tested at the Virginia Tech Stability Wind Tunnel. Since phased array technologies present some issues leading to misinterpretation of results and inaccuracy in determining actual levels, a new approach to the deconvolution of acoustic sources has been developed. The goal of this post-processing is to "simplify" the beamforming output by suppressing the sidelobes and reducing the sources mainlobe to a small number of points that accurately identify the noise sources position and their actual levels. To this end, the beamforming output is modeled as a superposition of "complex" point spread functions and a nonlinear system of equations is posted. Such system is solved using a new 2-step procedure. In the first step an approximated linear problem is solved, while in the second step an optimization is performed over the nonzero values obtained in the previous step. The solution to this system of equations renders the sources position and amplitude. The technique is called: noise source Localization and Optimization of Array Results (LORE). Numerical simulations as well as sample experimental results are shown for the proposed post-processing.en_US
dc.publisherVirginia Techen_US
dc.relation.haspartDissertation_Patricio_Ravetta.pdfen_US
dc.rightsI hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to Virginia Tech or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.en_US
dc.subjectNoise Control Devicesen_US
dc.subjectAeroacousticsen_US
dc.subjectBeamformingen_US
dc.subjectDeconvolutionen_US
dc.subjectPhased Arrayen_US
dc.subjectLanding Gear Noiseen_US
dc.titleLORE Approach for Phased Array Measurements and Noise Control of Landing Gearsen_US
dc.typeDissertationen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplineMechanical Engineeringen_US
dc.contributor.committeechairBurdisso, Ricardo A.en_US
dc.contributor.committeememberJohnson, Martin E.en_US
dc.contributor.committeememberWicks, Alfred L.en_US
dc.contributor.committeememberKhorrami, Mehdien_US
dc.contributor.committeememberStoker, Roberten_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-12072005-113549/en_US
dc.contributor.committeecochairNg, Faien_US
dc.date.sdate2005-12-07en_US
dc.date.rdate2006-12-29
dc.date.adate2005-12-29en_US


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