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dc.contributor.authorNewman, James Charles IIIen_US
dc.date.accessioned2014-03-14T20:22:33Z
dc.date.available2014-03-14T20:22:33Z
dc.date.issued1997-07-22en_US
dc.identifier.otheretd-81597-143335en_US
dc.identifier.urihttp://hdl.handle.net/10919/30711
dc.description.abstractThe first two steps in the development of an integrated multidisciplinary design optimization procedure capable of analyzing the nonlinear fluid flow about geometrically complex aeroelastic configurations have been accomplished in the present work. For the first step, a three-dimenstional unstructured grid approach to earodynamic shape sensitivity analysis and design optimization has been developed. The advantage of unstructured grids, when compared with a structured-grid approach, is their inherent ability to discretize irregularly shaped domains with greater efficiency and less effort. Hence, this approach is ideally suited fro geometrically complex configurations of practical interest. In this work the time-dependent, nonlinear Euler equations are solved using an upwind, cell-centered, finite-volume scheme. The descrete, linearized systems which result from this scheme are solved iteratively by a preconditioned conjugate-gradient-like algorithm known as GMRES for the two-dimensional cases and a Gauss-Seidel algorithm for the three-dimensional; at steady-state, similar procedures are used to solve the accompanying linear aerodynamic sensitivitiy equations in incremental iterative form. As shown, this particular form of the sensitivity equation makes large-scale gradient-based aerodynamic optimization possible bytaking advantage of memory efficient methods to construct exact Jacobian matrix-vector products. Various surface parameterization techniques have been employed in the current study to control the shape of the design surface. Once this surface has been deformed, the interior volume of the unstructured grid is adapted by considering the mesh as a system of interconnected tension springs. Grid sensitivities are obtained by differentiating the surface parameterization and the grid adaptiation algorithms with ADIFOR, an advanced automatic-differentiation software tool. To demonstrate the ability of this procedure to analyze and design complex configurations of practical interest, the sensitivity analysis and shape optimization has been performaed for several two- and three-dimensional cases. In two-dimensions, an initially symmetric NACA-0012 airfoil and a high-lift multielement airfoil were examined. For the three-dimensional configurations, an initially rectangular wing with uniform NACA-0012 cross-scetions was optimized; in additions, a complete Boeing 747-200 aircraft was studied. Furthermore, the current study also examines the effect of inconsistency in the order of spatial accuracy between the nonlinear fluid and linear shape sensitivity equations.

The second step was to develop a computationally efficient, high-fidelity, integrated static aeroelastic analysis procedure. To accomplish this, a structural analysis code was coupled with the aforementioned unstructured grid aerodynamic analysis solver. The use of an unstructured grid scheme for the aerodynamic analysis enhances the interactions compatibility with the wing structure. The structural analysis utilizes finite elements to model the wing so that accurate structural deflections may be obtained. In the current work, paramenters have been introduced to control the interaction of the computational fluid dynamics and structural analyses; these control parameters permit extremely efficient static aeroelastic computations. To demonstrate and evaluate this procedure, static aeroelastic analysis results for a flexible wing in low subsonic, high subsonic (subcritical), transonic (supercritical), and supersonic flow conditions are presented.

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dc.publisherVirginia Techen_US
dc.relation.hasparttitlepage_pdf.pdfen_US
dc.relation.haspartabstract.pdfen_US
dc.relation.haspartacknowledgments.pdfen_US
dc.relation.haspartappendices.pdfen_US
dc.relation.haspartchapter1.pdfen_US
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dc.relation.haspartNFIG6-9.PDFen_US
dc.relation.haspartNVITA1.PDFen_US
dc.rightsI hereby grant to Virginia Tech or its agents the right to archive and to make available my thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. I retain all proprietary rights, such as patent rights. I also retain the right to use in future works (such as articles or books) all or part of this thesis or dissertation.en_US
dc.subjectStatic Aeroelastic Analysisen_US
dc.subjectUnstructured Gridsen_US
dc.subjectAerodynamic Shape Optimizationen_US
dc.titleIntegrated Multidisciplinary Design Optimization Using Discrete Sensitivity Analysis for Geometrically Complex Aeroelastic Configurationsen_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.committeechairBarnwell, Richard W.en_US
dc.contributor.committeememberWest, Robert L. Jr.en_US
dc.contributor.committeememberNg, Wing Faien_US
dc.contributor.committeememberScott, Elaine P.en_US
dc.contributor.committeememberTaylor, A. C.en_US
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-81597-143335/en_US
dc.date.sdate1997-07-22en_US
dc.date.rdate1997-10-06
dc.date.adate1997-10-06en_US


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