Scholarly
    Communications Project


Document Type:Dissertation
Name:James Charles Newman III
Email address:newman@Ae.MsState.Edu
URN:1997/00203
Title:Integrated Multidisciplinary Design Optimization Using Discrete Sensitivity Analysis for Geometrically Complex Aeroelastic Configurations
Degree:Doctor of Philosophy
Department:Mechanical Engineering
Committee Chair: R. W. Barnwell
Chair's email:rbarnwel@vt.edu
Committee Members:A. C. Taylor
E. P. Scott
R. L. West
W. F. Ng
Keywords:Static Aeroelastic Analysis, Unstructured Grids, Aerodynamic Shape Optimization
Date of defense:July 22, 1997
Availability:Release the entire work for Virginia Tech access only.
After one year release worldwide only with written permission of the student and the advisory committee chair.

Abstract:

The 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.



List of attached files

File NameSize (Bytes)
abstract.pdf5,243 Bytes
acknowledgments.pdf3,833 Bytes
appendices.pdf74,000 Bytes
chapter1.pdf43,664 Bytes
chapter2.pdf23,561 Bytes
chapter3.pdf45,174 Bytes
chapter4.pdf39,078 Bytes
chapter5.pdf12,338 Bytes
chapter6.pdf37,888 Bytes
chapter7.pdf10,003 Bytes
copyright.pdf1,469 Bytes
fig4-1.pdf376,525 Bytes
fig5-1a2.pdf5,967 Bytes
fig6-1.pdf148,401 Bytes
fig6-10.pdf33,794 Bytes
fig6-11.pdf1,469,850 Bytes
fig6-12.pdf1,509,857 Bytes
fig6-13.pdf1,588,708 Bytes
fig6-14.pdf7,157 Bytes
fig6-15.pdf5,720,387 Bytes
fig6-16.pdf210,771 Bytes
fig6-17.pdf5,826,101 Bytes
fig6-18.pdf5,827,114 Bytes
fig6-19.pdf46,920 Bytes
fig6-2.pdf490,098 Bytes
fig6-20.pdf129,626 Bytes
fig6-21.pdf77,408 Bytes
fig6-22.pdf84,310 Bytes
fig6-23.pdf71,063 Bytes
fig6-24.pdf1,675,657 Bytes
fig6-24C.pdf1,667,966 Bytes
fig6-3.pdf16,142 Bytes
fig6-4.pdf29,048 Bytes
fig6-5.pdf579,452 Bytes
fig6-6.pdf861,439 Bytes
fig6-7.pdf13,137 Bytes
fig6-8.pdf922,103 Bytes
lof.pdf4,680 Bytes
lot.pdf2,068 Bytes
nomenclature.pdf6,038 Bytes
phdcover.pdf92,414 Bytes
readme-please.pdf2,119 Bytes
references.pdf43,676 Bytes
tables_p_75.pdf4,993 Bytes
tables_p_76.pdf6,214 Bytes
titlepage_pdf.pdf2,341 Bytes
toc.pdf5,977 Bytes

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